Tape measures speak feet-and-inches
US construction measures in feet and fractional inches, and adding 5′9″ to 27 inches is daily arithmetic that's easy to fumble. The calculator converts any feet-plus-inches combination to total inches, adds an amount, and formats the result back into the feet-and-inches form your tape reads.
Sources and standards
Where these figures come from
Every formula on this page is implemented from the published reference material below. Where a value depends on a regional code, the calculator lets you override it rather than assuming one jurisdiction.
- NIST Office of Weights and Measures — the US customary and SI conversion factors used throughout this tool.
- International Code Council — the International Residential Code and International Building Code.
Figures, formulas and reference tables last verified: 19 September 2026.