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Professional Window & Door Frame Size Calculator
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Rough Opening Size Comparison
Standard Reference Tables
Window Clearance Standards (per most building codes)
| Nominal Size | Frame Width | Rough Opening Width (Standard) | Rough Opening Width (Extra) |
|---|---|---|---|
| 2'6" × 3'6" | 30" × 42" | 31" × 43" | 31.5" × 43.5" |
| 3'0" × 3'6" | 36" × 42" | 37" × 43" | 37.5" × 43.5" |
| 3'6" × 4'6" | 42" × 54" | 43" × 55" | 43.5" × 55.5" |
| 4'0" × 4'6" | 48" × 54" | 49" × 55" | 49.5" × 55.5" |
| 5'0" × 4'6" | 60" × 54" | 61" × 55" | 61.5" × 55.5" |
Door Clearance Standards
| Door Type | Door Size | Frame Width | Rough Opening Width | Rough Opening Height |
|---|---|---|---|---|
| Single Entry | 2'8" × 6'8" | 32" | 33.5" - 34" | 82.5" - 83" |
| Single Entry | 3'0" × 6'8" | 36" | 37.5" - 38" | 82.5" - 83" |
| Double Entry | 5'4" × 6'8" | 64" | 65.5" - 66" | 82.5" - 83" |
| Single Pocket | 2'8" × 6'8" | 32" | 37" - 40" | 82.5" - 83" |
| Patio Door | 5'0" × 6'8" | 60" | 61.5" - 62" | 82.5" - 83" |
Resources & References
Helpful External Resources
Why Proper Rough Opening Sizing Matters
Accurate rough opening measurements are critical for successful window and door installation. Undersized openings can prevent proper installation and weatherproofing, while oversized openings lead to excessive shimming, poor performance, and potential water infiltration. Industry standards recommend specific clearances on all sides to accommodate frame material, insulation, and flashing details.
Always measure twice, consult manufacturer instructions, and verify with local building requirements before cutting openings.