🚿 Bathroom Renovation Calculator
Remodel costs, exhaust fan sizing, tile & material estimates
Bathroom Renovation Calculators
Flooring
Cabinets
Tile Work
Plumbing
Electrical
Painting
Toilet
Sink/Faucet
Shower/Tub
Pipes (supply/drain)
Ventilation/Fan
Water Heater
Bathroom Renovation Cost Guide
| Remodel Type | Cost Range | Cost per sq ft | Scope | Timeline |
|---|---|---|---|---|
| Cosmetic Only | $2,000-$5,000 | $40-100/sq ft | Paint, fixtures, hardware, lighting | 1-2 weeks |
| Minor Remodel | $5,000-$15,000 | $100-300/sq ft | New vanity, toilet, tile, flooring | 2-4 weeks |
| Standard Remodel | $15,000-$30,000 | $300-600/sq ft | New cabinets, tile, fixtures, some plumbing | 3-6 weeks |
| Major Remodel | $30,000-$50,000 | $600-1000/sq ft | Gut & remodel, new plumbing, electrical | 6-10 weeks |
| Luxury Renovation | $50,000+ | $1000+/sq ft | High-end everything, custom finishes | 8-12+ weeks |
💰 Cost Breakdown by Item
Cabinets/Vanity: $1,500-5,000 (30-50% of budget)
Flooring: $1,000-3,000 (materials + labor)
Tile (walls/shower): $2,000-5,000
Fixtures (toilet, sink, faucet): $800-2,500
Labor (50% of total in most cases): $5,000-25,000
Plumbing: $1,500-4,000 (if needed)
Electrical: $1,000-3,000 (if needed)
📊 ROI (Return on Investment)
✓ Cosmetic Remodel (50-75% ROI): Best return on investment
✓ Standard Remodel (50-60% ROI): Good value, adds home value
✓ Major Remodel (40-50% ROI): May not recover full cost at sale
✓ Luxury Remodel (30-40% ROI): Personal enjoyment over resale value
🏠 Average Bathroom Size Costs
Small (30-40 sq ft): $3,000-15,000 for standard remodel
Medium (50-80 sq ft): $8,000-30,000
Large (100+ sq ft): $15,000-50,000+
Bathroom Specifications & Standards
💨 Exhaust Fan CFM Requirements
IPC Code Standard: 1 CFM per square foot (minimum)
ASHRAE 62.2: 50 CFM minimum + 0.05 CFM per sq ft + 0.1 CFM per linear foot of shower
Steam Showers: 100-200+ CFM (high moisture)
Example: 50 sq ft bathroom = minimum 50 CFM (IPC) or 55-60 CFM (ASHRAE)
⚙️ Fan Sizing by Bathroom Size
• Small (under 50 sq ft): 50-75 CFM fan
• Medium (50-100 sq ft): 75-100 CFM fan
• Large (100-150 sq ft): 100-150 CFM fan
• Very Large (150+ sq ft): 150+ CFM or dual fans
📏 Standard Bathroom Dimensions
Powder Room (half bath): 20-40 sq ft (3×7 to 5×8 ft)
Small Full Bath: 40-50 sq ft (5×8 to 6×8 ft)
Standard Full Bath: 50-80 sq ft (6×8 to 8×10 ft)
Master Bath: 80-150+ sq ft (8×10 to larger)
🔧 Code & Compliance
✓ Exhaust fan required by code in almost all jurisdictions
✓ Must duct to exterior (not attic or crawlspace)
✓ Duct should be minimum 4" diameter
✓ Damper required on exterior vent
✓ Timer or humidity sensor recommended
🎨 Tile Coverage Estimates
Shower Surround: 2.5 sq ft of tile per linear foot height
Bathroom Floor: Total square footage + 10% waste
Backsplash: Measure height × length + 10% waste
Waste Factor: 10-15% extra for cuts, breakage, future repairs
⚡ Electrical Requirements
• GFCI outlet required within 6 feet of sink
• Minimum 1 outlet, 20-amp circuit recommended
• Exhaust fan requires separate circuit (dedicated)
• Lighting: 50-80 lumens per sq ft (vanity needs 400+ lumens)
Bathroom Renovation
Calculator Guide
Cost · CFM · Tile · Square Footage · Lumens · BTU · Regional Pricing
The Complete Homeowner Reference — 2025 / 2026 Edition
Planning a bathroom renovation without accurate numbers is the fastest way to blow your budget. This guide brings together all the essential bathroom calculators in one place, from remodel cost estimates and exhaust fan CFM sizing to tile quantities, square footage, lighting levels, heating capacity, and regional pricing worldwide.
How to Use This Guide: You can either work through the guide section by section to build a detailed, comprehensive renovation plan, or skip directly to the calculators and topics most relevant to your project. Each section is designed as a standalone reference so you can find answers quickly, no matter where you start.
1. Bathroom Remodel Cost Calculator
The average bathroom remodel cost in 2025 is approximately $12,125, with most homeowners spending between $6,639 and $17,621. The final figure depends on bathroom size, scope of work, material grade, and local labour rates. Use the step-by-step formula below to build your personal estimate.
Step-by-Step Bathroom Remodel Cost Formula
Step 1 — Measure Bathroom Square Footage
📐 Length (ft) × Width (ft) = Square Footage
Step 2 — Choose Your Remodel Level
Remodel Level | Cost Per Sq. Ft. | Typical Total | What Is Included |
| Basic Refresh | $50 – $100 | $2,500 – $5,000 | Paint, fixtures, hardware, accessories |
| Mid-Range Remodel | $100 – $300 | $6,000 – $18,000 | New tile, vanity, toilet, shower updates |
| Full Renovation | $300 – $500 | $18,000 – $35,000 | Complete gut, layout changes, premium finishes |
| Luxury Renovation | $500+ | $35,000 – $80,000+ | Custom everything, high-end materials, spa features |
Step 3 — Calculate Your Estimate
📐 Square Footage × Cost Per Sq. Ft. = Estimated Total
💡 Example: A 50 sq. ft. bathroom at mid-range level = 50 × $200 = $10,000 estimated
Cost Breakdown by Component
Understanding where the money goes helps you prioritise and find savings opportunities.
Component | % of Budget | Typical Cost Range |
| Labour (all trades) | 40 – 65% | $3,000 – $12,000 |
| Shower / Tub | 20 – 25% | $1,500 – $15,000 |
| Vanity & Countertop | 10 – 15% | $500 – $3,500 |
| Flooring & Tile | 10 – 15% | $800 – $4,500 |
| Toilet | 3 – 5% | $300 – $1,000 |
| Plumbing | 5 – 15% | $500 – $5,000 |
| Electrical & Lighting | 3 – 8% | $300 – $2,500 |
| Ventilation Fan | 1 – 3% | $200 – $600 |
| Demolition | 3 – 8% | $600 – $2,300 |
| Permits & Miscellaneous | 2 – 5% | $200 – $1,500 |
Remodel Cost by Bathroom Type
Bathroom Type | Typical Size | Average Remodel Cost |
| Half Bath / Powder Room | 15 – 30 sq. ft. | $1,500 – $7,500 |
| Small Full Bathroom | 35 – 50 sq. ft. | $3,500 – $12,000 |
| Standard Full Bathroom | 50 – 70 sq. ft. | $6,000 – $18,000 |
| Master / Primary Bathroom | 80 – 150 sq. ft. | $7,000 – $30,000 |
| Luxury Master Bathroom | 150+ sq. ft. | $30,000 – $80,000+ |
| Basement Bathroom | 35 – 60 sq. ft. | $10,000 – $25,000 |
Labour Cost Calculator
Labour typically accounts for 40–65% of a bathroom remodel budget, with 50% being the most commonly cited average.
📐 Total Project Cost × 0.50 = Estimated Labour Cost
💡 Example: $12,000 project × 0.50 = $6,000 estimated labour
Trade / Specialist | Hourly Rate | When Needed |
| General Contractor | $65 – $100/hr | Project management, full renovations |
| Plumber | $75 – $150/hr | Moving pipes, new fixtures, rough-in work |
| Electrician | $50 – $130/hr | New circuits, lighting, exhaust fan wiring |
| Tile Installer | $35 – $130/hr | Floor and wall tiling |
| Carpenter / Cabinetmaker | $50 – $120/hr | Custom vanities, built-ins, millwork |
Fixture Cost Reference
Fixture | Budget | Mid-Range | Premium |
| Toilet | $150 – $350 | $350 – $700 | $700 – $2,000+ |
| Vanity (single) | $200 – $600 | $600 – $1,500 | $1,500 – $5,000+ |
| Bathtub | $300 – $800 | $800 – $2,500 | $2,500 – $8,000+ |
| Shower (prefab) | $500 – $1,500 | $1,500 – $4,000 | $4,000 – $15,000+ |
| Faucet | $50 – $200 | $200 – $500 | $500 – $2,000+ |
| Mirror | $50 – $200 | $200 – $600 | $600 – $2,000+ |
| Exhaust Fan | $30 – $80 | $80 – $200 | $200 – $500+ |
| Lighting | $50 – $200 | $200 – $500 | $500 – $2,000+ |
| Bathroom Sink | $50 – $250 | $250 – $700 | $700 – $3,000+ |
Material Cost Calculator
📐 Total Project Cost × 0.40 = Estimated Material Cost
📐 Material Budget × Component % = Budget Per Component
💡 Example: $12,000 project → $4,800 materials → Tile (12%) = $576
2. Bathroom Square Footage Calculator
Calculating your bathroom’s square footage accurately is the foundation of every other calculation in this guide — from tile quantities to fan sizing to renovation cost estimates.
How to Calculate Bathroom Square Footage
Rectangular or Square Bathroom
📐 Length (ft) × Width (ft) = Square Footage
💡 Example: 8 ft × 10 ft = 80 sq. ft.
Irregular or L-Shaped Bathroom
Divide the space into smaller rectangles, calculate each area separately, and add the results.
- Step 1: Sketch the floor plan
- Step 2: Divide the plan into rectangles
- Step 3: Calculate each rectangle: Length × Width
- Step 4: Add all results
💡 Example: Main area 8×6 = 48 sq. ft. + Shower alcove 4×3 = 12 sq. ft. = 60 sq. ft. total
Converting Square Feet to Square Metres
📐 Square Feet ÷ 10.764 = Square Metres
Bathroom Volume Calculator
Volume is needed for exhaust fan CFM and BTU heating calculations.
📐 Length (ft) × Width (ft) × Ceiling Height (ft) = Volume (cubic feet)
💡 Example: 8 ft × 10 ft × 8 ft = 640 cubic feet
Bathroom Size Reference Chart
Bathroom Type | Typical Sq. Ft. | Typical Dimensions |
| Powder / Half Bath | 15 – 30 sq. ft. | 5 ft × 4 ft to 6 ft × 5 ft |
| Small Full Bath | 35 – 50 sq. ft. | 5 ft × 7 ft to 6 ft × 8 ft |
| Standard Full Bath | 50 – 70 sq. ft. | 7 ft × 8 ft to 8 ft × 9 ft |
| Large Full Bath | 70 – 100 sq. ft. | 9 ft × 9 ft to 10 ft × 10 ft |
| Master / Primary Bath | 100 – 160 sq. ft. | 10 ft × 12 ft to 12 ft × 14 ft |
| Luxury Master Bath | 160+ sq. ft. | 13 ft × 14 ft and above |
3. Bathroom Exhaust Fan CFM Calculator
CFM stands for Cubic Feet per Minute — the standard unit for measuring how much air a fan moves per minute. The goal is to change the air in your bathroom 8 times per hour, which is the standard set by the Home Ventilating Institute (HVI).
Method 1 — CFM by Square Footage (Bathrooms Under 100 Sq. Ft.)
The simplest method is widely used for standard residential bathrooms.
📐 Square Footage × 1 CFM = Minimum Required CFM
- Step 1: Measure Length × Width = Sq. Ft.
- Step 2: Apply 1 CFM per sq. ft.
- Step 3: Round up to the nearest fan size (50, 70, 80, 100, 110, 130, 150 CFM)
- Step 4: Never go below 50 CFM — this is the minimum building code requirement
💡 Example: 8 ft × 9 ft = 72 sq. ft. → Minimum 80 CFM fan (round up, never down)
Method 2 — CFM by Volume (Most Accurate)
This is the most accurate method for any bathroom, especially those with high ceilings or unusual proportions.
📐 (Length × Width × Ceiling Height) ÷ 60 × 8 = Required CFM
- Step 1: Calculate volume: Length × Width × Height
- Step 2: Divide volume by 60 (converts hours to minutes)
- Step 3: Multiply by 8 (recommended air changes per hour)
- Step 4: Round up to the nearest available fan size
💡 Example: 8 ft × 10 ft × 8 ft = 640 cu. ft. → 640 ÷ 60 = 10.67 → 10.67 × 8 = 85.3 → Select 90 or 100 CFM fan
Method 3 — CFM by Fixtures (Bathrooms Over 100 Sq. Ft.)
For larger bathrooms, the HVI recommends calculating based on the number and type of plumbing fixtures.
Fixture | CFM to Add |
| Toilet | 50 CFM |
| Shower (standard) | 50 CFM |
| Bathtub | 50 CFM |
| Jetted / Whirlpool Tub | 100 CFM |
| Double / Steam Shower | 100 CFM |
📐 Sum of All Fixture CFM Values = Required Fan CFM
💡 Example: Toilet (50) + Shower (50) + Bathtub (50) = 150 CFM minimum
Bathroom Fan CFM Quick-Reference Chart
Bathroom Size (Sq. Ft.) | 7 ft Ceiling | 8 ft Ceiling | 9 ft Ceiling | 10 ft Ceiling |
| Up to 30 sq. ft. | 50 CFM | 50 CFM | 50 CFM | 50 CFM |
| 31 – 50 sq. ft. | 50 CFM | 50 CFM | 60 CFM | 70 CFM |
| 51 – 70 sq. ft. | 60 CFM | 75 CFM | 80 CFM | 90 CFM |
| 71 – 90 sq. ft. | 80 CFM | 90 CFM | 100 CFM | 110 CFM |
| 91 – 110 sq. ft. | 100 CFM | 110 CFM | 120 CFM | 130 CFM |
| 111 – 130 sq. ft. | 120 CFM | 130 CFM | 140 CFM | 150 CFM |
| 131 – 150 sq. ft. | 140 CFM | 150 CFM | 160 CFM | 170 CFM |
| 151 – 200 sq. ft. | 160 CFM | 180 CFM | 200 CFM | 220 CFM |
💡 Always use the HIGHER result when comparing the square footage method and the fixture method. Always round UP to the nearest available fan size.
High-Ceiling CFM Adjustment
📐 Standard CFM × (Actual Ceiling Height ÷ 8) = Adjusted CFM
💡 Example: 80 CFM × (10 ÷ 8) = 80 × 1.25 = 100 CFM
Fan Size Selection Guide
Fan CFM | Suitable For |
| 50 CFM | Powder rooms and bathrooms under 50 sq. ft. |
| 70 – 80 CFM | Standard bathrooms 50 – 75 sq. ft. |
| 90 – 110 CFM | Medium bathrooms 75 – 100 sq. ft., or any bath with a shower |
| 120 – 150 CFM | Large bathrooms 100 – 150 sq. ft., or baths with multiple fixtures |
| 150 – 200 CFM | Master bathrooms 150+ sq. ft., steam showers, or jetted tubs |
| 200+ CFM | Luxury master baths, multiple simultaneous users, very high ceilings |
Complete CFM Calculation: Step-by-Step Summary
- Measure your bathroom: Length × Width = Sq. Ft.
- Measure ceiling height
- Calculate volume: Sq. Ft. × Ceiling Height = Cubic Feet
- Volume method: (Volume ÷ 60) × 8 = Base CFM
- Count fixtures and add their CFM values
- Take the HIGHER of the two results.
- Add 10–15% for long duct runs or multiple elbows.
- Round UP to the nearest available fan size.
4. Bathroom Tile Calculator
The tile calculation process is the same for floors and walls. The key is to measure each surface accurately and apply the correct waste factor for your chosen layout.
Step 1 — Calculate the Area to be Tiled
Floor Tiles
📐 Length (ft) × Width (ft) = Floor Area (sq. ft.)
Wall Tiles
📐 Width of Wall (ft) × Height of Wall (ft) = Wall Area (sq. ft.)
Measure and calculate each wall separately, then add the totals. Subtract window, door, and fixture openings.
Step 2 — Add a Waste Factor
Tile Layout | Waste Factor to Add |
| Straight / grid layout (tiles aligned with walls) | Add 10% |
| Diagonal / 45° layout | Add 15% |
| Herringbone or complex pattern | Add 20% |
| Large format tiles (24″ × 24″ and above) | Add 10 – 15% |
📐 Area (sq. ft.) × (1 + Waste Factor) = Total Tiles Needed (sq. ft.)
💡 Example: 80 sq. ft. floor, straight layout: 80 × 1.10 = 88 sq. ft. to order
Step 3 — Convert to Number of Tiles
📐 Tile Length (in) × Tile Width (in) ÷ 144 = Sq. Ft. Per Tile
📐 Total Area Needed (sq. ft.) ÷ Sq. Ft. Per Tile = Number of Tiles
Tile Size Reference Chart
Tile Size | Sq. Ft. Per Tile | Tiles Per 100 Sq. Ft. |
| 4″ × 4″ | 0.11 sq. ft. | ~900 tiles |
| 6″ × 6″ | 0.25 sq. ft. | ~400 tiles |
| 12″ × 12″ | 1.00 sq. ft. | ~100 tiles |
| 12″ × 24″ | 2.00 sq. ft. | ~50 tiles |
| 18″ × 18″ | 2.25 sq. ft. | ~44 tiles |
| 24″ × 24″ | 4.00 sq. ft. | ~25 tiles |
| 3″ × 12″ (subway) | 0.25 sq. ft. | ~400 tiles |
| 4″ × 16″ (subway) | 0.44 sq. ft. | ~225 tiles |
Tile Cost Calculator
Tile Type | Material Cost/Sq. Ft. | Installed Cost/Sq. Ft. |
| Basic ceramic | $0.50 – $3.00 | $5 – $10 |
| Porcelain | $2.00 – $10.00 | $7 – $15 |
| Natural stone (travertine) | $5.00 – $15.00 | $12 – $25 |
| Marble | $10.00 – $40.00 | $18 – $40 |
| Mosaic / glass | $5.00 – $30.00 | $12 – $30 |
| Large format (24×24″+) | $4.00 – $20.00 | $10 – $25 |
📐 Sq. Ft. Needed × Material Rate + Sq. Ft. Needed × Labour Rate = Total Tile Cost
💡 Example: 90 sq. ft. porcelain at $5 material + $10 labour = $450 + $900 = $1,350 total
Shower Wall Tile Calculation
📐 (Wall 1 Width + Wall 2 Width + …) × Tile Height = Total Wall Area
💡 Example: Three shower walls 3+4+3 ft = 10 ft × 8 ft height = 80 sq. ft. + 10% = 88 sq. ft.
5. Bathroom Lighting Lumens Calculator
Lumens measure the total output of light from a fixture. Unlike watts (which measure energy use), lumens tell you how bright a light source actually is. Always use lumens — not watts — when calculating bathroom lighting needs.
Recommended Lumens Per Square Foot
Area / Task | Recommended Lumens Per Sq. Ft. |
| General ambient lighting | 70 – 80 lumens / sq. ft. |
| Vanity / grooming area | 150 – 200 lumens / sq. ft. (at task level) |
| Shower area | 80 – 100 lumens / sq. ft. |
| Night lighting / accent | 10 – 20 lumens / sq. ft. |
📐 Bathroom Sq. Ft. × Lumens Per Sq. Ft. = Total Lumens Needed
💡 Example: 60 sq. ft. × 75 lumens = 4,500 total lumens for general ambient lighting
Number of Fixtures Needed
📐 Total Lumens Needed ÷ Lumens Per Fixture = Number of Fixtures
💡 Example: 4,500 lumens ÷ 1,600 per fixture = 2.8 → Install 3 fixtures minimum
Lumens to Bulb Reference
Lumens Output | LED Wattage | Old Incandescent Equivalent |
| 450 lumens | ~6W | 40W |
| 800 lumens | ~9W | 60W |
| 1,100 lumens | ~13W | 75W |
| 1,600 lumens | ~18W | 100W |
| 2,600 lumens | ~28W | 150W |
Bathroom Lumens Quick-Reference Chart
Bathroom Size | General Lighting (Total Lumens) | Additional Vanity Task Lighting |
| 20 – 30 sq. ft. | 1,500 – 2,400 | Add 2,000 – 3,000 at mirror |
| 35 – 50 sq. ft. | 2,500 – 4,000 | Add 3,000 – 4,000 at mirror |
| 50 – 70 sq. ft. | 3,500 – 5,600 | Add 3,000 – 5,000 at mirror |
| 70 – 100 sq. ft. | 4,900 – 8,000 | Add 4,000 – 6,000 at mirror |
| 100 – 150 sq. ft. | 7,000 – 12,000 | Add 5,000 – 8,000 at mirror |
6. Bathroom BTU Heating Calculator
BTU (British Thermal Unit) is the unit used to measure heating capacity. For bathroom radiators, towel rails, and electric heaters, selecting the right BTU ensures the space heats efficiently and reaches a comfortable temperature.
How to Calculate BTU for a Bathroom
Step 1 — Calculate Bathroom Volume
📐 Length × Width × Ceiling Height = Volume (cubic feet)
Step 2 — Apply the BTU Formula
Bathrooms require a higher multiplier than other rooms because of heat loss through tiled floors and walls, and the need to heat the space quickly from cold.
📐 Volume (cubic feet) × 4 = Estimated BTU Required
💡 Example: 8 ft × 10 ft × 8 ft = 640 cu. ft. → 640 × 4 = 2,560 BTU minimum
BTU Adjustment Factors
Condition | Adjustment |
| Ground floor or poorly insulated floor | Add 15% |
| External wall facing north | Add 10% |
| Two or more external walls | Add 20% |
| Large window (over 20% of wall area) | Add 10% per large window |
| Well-insulated modern home | Reduce by 10% |
BTU Quick-Reference Chart
Bathroom Size | Standard BTU | Large Window | Ground Floor / Older |
| 20 – 30 sq. ft. | 640 – 960 | 700 – 1,060 | 740 – 1,100 |
| 35 – 50 sq. ft. | 1,120 – 1,600 | 1,230 – 1,760 | 1,290 – 1,840 |
| 50 – 70 sq. ft. | 1,600 – 2,240 | 1,760 – 2,460 | 1,840 – 2,580 |
| 70 – 100 sq. ft. | 2,240 – 3,200 | 2,460 – 3,520 | 2,580 – 3,680 |
| 100 – 150 sq. ft. | 3,200 – 4,800 | 3,520 – 5,280 | 3,680 – 5,520 |
Converting BTU to Watts (Electric Heaters)
📐 BTU ÷ 3.412 = Watts
💡 Example: 2,560 BTU ÷ 3.412 = 750 Watts
7. Bathroom Renovation Costs by Region
Renovation costs vary significantly by country, state, and city. Use these regional figures as a planning baseline, then adjust for your local labour market and material availability.
United States — Bathroom Renovation Cost Calculator
Region | Cost Per Sq. Ft. | Average Full Remodel Cost |
| Northeast (NY, MA, CT) | $200 – $500 | $15,000 – $40,000 |
| Mid-Atlantic (VA, MD, PA) | $150 – $350 | $10,000 – $28,000 |
| Southeast (FL, GA, NC) | $100 – $250 | $7,000 – $20,000 |
| Midwest (IL, OH, MN) | $100 – $250 | $7,000 – $20,000 |
| Southwest / Texas (TX, AZ) | $120 – $300 | $8,000 – $24,000 |
| West Coast (CA, OR, WA) | $200 – $500 | $15,000 – $40,000 |
Canada — Bathroom Renovation Cost Calculator
Province / Region | Average Cost (CAD) |
| Ontario | $12,000 – $30,000 |
| British Columbia | $14,000 – $35,000 |
| Alberta | $10,000 – $25,000 |
| Quebec | $9,000 – $22,000 |
| National Average | $10,000 – $25,000 CAD |
United Kingdom — Bathroom Renovation Cost Calculator
Project Type | Estimated Cost (GBP) |
| Basic refresh | £1,500 – £4,000 |
| Mid-range full renovation | £4,000 – £10,000 |
| Premium / luxury renovation | £10,000 – £25,000+ |
| Labour only (fitting) | £1,500 – £4,500 |
| Supply and fit (mid-range) | £5,000 – £12,000 |
| Small bathroom renovation (UK) | £2,500 – £6,000 |
💡 UK Regional note: Expect to pay 30–50% more in London and the Southeast compared to the national average.
Australia — Bathroom Renovation Cost Calculator
Project Type | Estimated Cost (AUD) |
| Small bathroom renovation | $8,000 – $18,000 |
| Full standard renovation | $18,000 – $35,000 |
| Luxury renovation | $35,000 – $70,000+ |
| Cost per sq. metre | $1,500 – $5,000 / sq. m. |
New Zealand — Bathroom Renovation Cost Calculator
Project Type | Estimated Cost (NZD) |
| Basic renovation | $10,000 – $20,000 |
| Full renovation | $20,000 – $40,000 |
| Premium renovation | $40,000 – $80,000+ |
India — Bathroom Renovation Cost Calculator
Project Type | Estimated Cost (INR) |
| Basic renovation | ₹50,000 – ₹1,50,000 |
| Mid-range renovation | ₹1,50,000 – ₹4,00,000 |
| Premium renovation | ₹4,00,000 – ₹10,00,000+ |
| Cost per sq. ft. | ₹1,500 – ₹5,000 / sq. ft. |
Ireland — Bathroom Cost Calculator
Project Type | Estimated Cost (EUR) |
| Basic bathroom refresh | €2,000 – €5,000 |
| Mid-range renovation | €5,000 – €12,000 |
| Premium renovation | €12,000 – €25,000+ |
8. Bathroom Demolition Cost Calculator
Demolition is often the first — and most underestimated — cost in a bathroom renovation. Most contractors charge $600 to $2,300 for full bathroom demolition when priced as a separate line item.
Demolition Cost by Scope
Scope of Demolition | Typical Cost |
| Fixture removal only (toilet, vanity, tub) | $200 – $600 |
| Floor tile removal | $2 – $6 per sq. ft. |
| Wall tile removal | $3 – $8 per sq. ft. |
| Full gut (all tiles, drywall, fixtures) | $1,000 – $2,500 |
| Drywall removal | $0.50 – $1.50 per sq. ft. |
| Subfloor removal | $1 – $3 per sq. ft. |
| Hazardous material testing & removal (asbestos/lead) | $500 – $3,000+ |
📐 Floor Area × Floor Demo Rate + Wall Area × Wall Demo Rate + Fixture Removal = Total Demo Cost
💡 Example: 50 sq. ft. bathroom full gut: Floor $200 + Wall tile $600 + Fixtures $400 = $1,200 estimated
9. Bathroom Addition Cost Calculator
Adding a new bathroom — converting a closet, finishing a basement, or building an addition — is one of the highest-value home improvement projects and typically returns 50–70% of its cost at resale.
Cost to Add a Bathroom
Project Type | Estimated Cost |
| Convert existing space (closet, corner) | $5,000 – $15,000 |
| Add bathroom to finished basement | $10,000 – $25,000 |
| Add bathroom to unfinished basement | $8,000 – $20,000 |
| Build a new addition | $20,000 – $75,000+ |
| Add a half bath / powder room | $3,000 – $10,000 |
| Loft bathroom addition | $15,000 – $40,000 |
| Attic bathroom installation | $12,000 – $35,000 |
Factors Affecting the Additional Cost
- Distance from existing plumbing — the further the new bathroom is, the more expensive the new pipe runs will be
- Above- or below-grade — basement additions may require upflush toilet systems, increasing costs.
- Permits — budget $200 – $1,500 for permits, depending on your location
- Structural changes — moving or reinforcing walls increases costs significantly
10. Bathroom Mirror Size Calculator
Choosing the right mirror size is both a functional and aesthetic decision. A mirror that is too narrow looks out of proportion; one that is too wide overwhelms the vanity.
Mirror Width Formula
📐 Vanity / Sink Width − 2 to 4 inches on each side = Ideal Mirror Width
💡 Example: 36-inch vanity → ideal mirror width is 28 to 32 inches
Mirror Height Formula
📐 Distance from Top of Backsplash to Ceiling × 0.75 = Suggested Mirror Height
💡 Example: 24 inches of wall space × 0.75 = 18-inch mirror height
Mirror Size Quick-Reference Chart
Vanity Width | Recommended Mirror Width | Recommended Mirror Height |
| 24 inches | 18 – 22 inches | 24 – 30 inches |
| 30 inches | 24 – 28 inches | 24 – 36 inches |
| 36 inches | 28 – 34 inches | 24 – 40 inches |
| 48 inches | 40 – 46 inches | 28 – 40 inches |
| 60 inches | 52 – 58 inches | 28 – 42 inches |
| 72 inches | 64 – 70 inches | 28 – 42 inches |
11. Frequently Asked Questions
Q: How do I calculate the cost of a bathroom renovation?
Multiply your bathroom’s square footage by the cost per square foot for your chosen remodel level — $50–$100 for a basic refresh, $100–$300 for mid-range, and $300–$500+ for a full luxury renovation. Add a 10–15% contingency buffer. Always obtain at least three contractor quotes before finalising your budget.
Q: How do I calculate CFM for a bathroom exhaust fan?
Use the volume method: multiply the room’s length, width, and ceiling height to get cubic feet. Divide by 60, then multiply by 8 (recommended air changes per hour). For bathrooms over 100 sq. ft., use the fixture method: add 50 CFM for each toilet, shower, and bathtub, and 100 CFM for a jetted tub. Use whichever result is higher, and always round up.
Q: How do I calculate how many tiles I need for a bathroom?
Measure the total area to be tiled. Add a 10% waste factor for straight layouts, 15% for diagonal, and 20% for complex patterns. Divide the adjusted total by the square footage of one tile. For 12×12-inch tiles (1 sq. ft. each), an 88 sq. ft. area (with 10% waste) requires 88 tiles.
Q: How do I calculate the square footage of a bathroom?
Measure the length and width in feet and multiply them. For irregular shapes, divide the space into rectangles, calculate each separately, then add the results. Include all floor area within the bathroom walls — do not subtract for fixtures or cabinets.
Q: How do I calculate lumens for a bathroom?
Multiply square footage by 70–80 lumens for general ambient lighting. For vanity and grooming, apply 150–200 lumens per square foot at the task level. A 60 sq. ft. bathroom needs approximately 4,200–4,800 lumens for general lighting, plus additional task lighting at the mirror.
Q: How do I calculate BTU for a bathroom heater or radiator?
Multiply the bathroom’s volume (length × width × ceiling height) by 4. A 640-cubic-foot bathroom needs approximately 2,560 BTU. Add 10–20% for external walls, poor insulation, or large windows. Divide BTU by 3.412 to convert to watts for electric heater sizing.
Q: What is the average cost of a bathroom remodel?
The national average in the United States is approximately $12,000–$12,500 for a full bathroom remodel, with most homeowners spending between $6,600 and $17,600. Small bathrooms typically cost $3,500–$12,000. Master bathrooms average $7,000–$30,000. Costs vary significantly by region, material grade, and scope.
Q: What percentage of a bathroom remodel is labour?
Labour typically accounts for 40–65% of the total cost, with 50% being the most commonly cited average. For a $12,000 project, expect $5,000–$7,000 in labour across all trades — plumber, electrician, tile installer, and general contractor.
Q: What is the minimum CFM for a bathroom fan?
The minimum CFM for any bathroom exhaust fan is 50 CFM, as required by most residential building codes. For bathrooms over 50 sq. ft., use 1 CFM per square foot as the minimum. Always round up to the next available fan size—never downsize.
Q: How do I calculate bathroom tile for walls?
Measure the width and height of each wall section to be tiled. Multiply width by height for each section. Add all sections together. Subtract window and door openings. Add 10–15% for waste. Divide the square footage by the square footage of your chosen tile size to get the number of tiles needed.
Q: How do I calculate the size of a bathroom exhaust fan for a high-ceiling bathroom?
Use the volume method rather than the square footage method. Multiply the actual ceiling height by the floor area to get the true volume, then apply (Volume ÷ 60) × 8 = Required CFM. For a 10 ft ceiling where you would normally use a 100 CFM fan, multiply by 10/8 = 1.25 to get 125 CFM.
Q: How do I calculate the cost of tiling a bathroom floor?
Measure the floor area in sq. ft. Add 10% for waste. Multiply by tile material cost ($0.50–$10/sq ft.) and separately by installation cost ($4–$12/sq ft.). Add both totals. A 55 sq. ft. floor (50 + 10% waste) at $5 material + $8 labour = $715 total.
Q: How much does it cost to remodel a main bathroom?
Main bathroom remodels average $7,000–$30,000 for mid-range finishes. High-end renovations with steam showers, heated floors, and custom tile can reach $30,000–$80,000 or more. Layout changes significantly increase cost by requiring new plumbing rough-in work.
Q: Are bathrooms included in home square footage calculations?
In real estate, bathrooms are typically included in a home’s total finished square footage. However, practices can vary by country and region. In most U.S. markets, all finished interior spaces, including bathrooms, are counted in the gross living area.
Q: How do I calculate CFM for a bathroom in a basement?
Use the same volume method: (Length × Width × Ceiling Height) ÷ 60 × 8 = Required CFM. Basement bathrooms often have lower ceilings, so the square-footage and volume methods may yield similar results. Ensure the exhaust duct runs are as short and straight as possible to maintain fan efficiency.
Q: How do I calculate the extraction rate for a bathroom extractor fan (UK)?
The UK Building Regulations recommend a minimum extraction rate of 15 litres per second (54 m³/hr) for intermittent fans in bathrooms. For continuous running fans, the recommended minimum flow rate is 8 litres per second (29 m³/hr). Use the same volume formula adapted for cubic metres: (Volume in m³) × 8 ÷ 60 = Required extraction in m³/min.
12. Disclaimer
The information and formulas provided in this guide are intended for general educational and planning purposes only. All cost estimates, calculation methods, and reference figures are based on general industry averages and may not reflect the specific conditions of your home, bathroom, or local market.
Cost Estimates: All renovation cost figures are approximate and based on general national or regional averages as of 2025–2026. Actual costs may be significantly higher or lower depending on your location, the condition of existing plumbing and structure, material choices, contractor pricing, and the scope of work. Always obtain at least three written quotes from licensed contractors before making financial decisions.
Calculator Formulas: The CFM, BTU, lumens, tile, and square footage formulas in this guide are based on widely used industry guidelines. They are starting-point estimates only. Local building codes, specific product specifications, and site conditions may result in different requirements. Always verify calculations against the product manufacturer’s specifications and your local building authority.
CFM and Ventilation: Bathroom ventilation requirements are governed by local building codes, which vary by jurisdiction. Always verify ventilation requirements with your local building code before installation.
Regional Pricing: Regional cost figures for Canada, the UK, Australia, New Zealand, India, and Ireland are approximate estimates. Exchange rates, local material availability, and labour market conditions change over time. Verify current pricing with local suppliers and contractors.
No Professional Advice: This guide does not constitute professional financial, engineering, plumbing, electrical, or construction advice. The authors and publishers accept no responsibility for any outcomes, costs, injuries, or damages arising from the use of information contained in this guide.
Always consult a licensed and qualified contractor, engineer, or specialist for advice specific to your home, project, and local requirements.