How to Calculate Door Rough Opening
What is Door Rough Opening?
Door Rough Opening Calculator helps contractors and tradespeople accurately size, spec, and estimate materials and systems.
Formula
RO Width = Door Width + 2 inches; RO Height = Door Height + 2.5 inches
Step-by-Step Guide
- 1Add framing clearance to door dimensions for rough opening
- 2Apply the formula using your project measurements
- 3Add required safety factors or waste allowances per code
Worked Examples
Input
32 inch × 80 inch door
Result
RO = 34 inches wide × 82.5 inches tall
Common Mistakes to Avoid
- ✕Not applying code-required safety factors or derating
- ✕Forgetting to account for waste and cut losses in material estimates
Ready to calculate? Try the free Door Rough Opening Calculator
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