Foot House Square Footage Calculator
Organize rooms by floor and add their measured areas. Keep your planning estimate separate from reported living area.
Plan your space
Add separate spaces; do not overlap them. Use a subtracting area for an island or fixture. Changing units reinterprets the numbers; re-enter dimensions in the selected unit. Assign each room to its floor. Each row is counted once.
Your measurements stay in this browser and the share link. No sign-up needed.
At a glance
Enter your measurements, then calculate.
Keep full precision while calculating. Round only when planning or ordering.
See formulas & sources ↗A simple way to measure
- Sketch the space and divide it into shapes that do not overlap.
- Enter each shape’s dimensions. For feet and inches, enter 10 and 6 for a 10 ft 6 in measurement.
- Add closets or separate spaces as new areas. Mark an island or other exclusion as a subtraction.
- Check the net area before adding a material allowance. Waste increases the order quantity; it does not increase your measured floor or land area.
Example: two spaces and a cutout
A 12 × 10 ft space is 120 sq ft. Add a 4 × 6 ft space and subtract a 2 × 3 ft fixture: the net is 138 sq ft. With 10% extra, plan for 151.8 sq ft.
Choose the right dimensions
For a circle, measure the radius from the center to the edge, not the full diameter. A triangle needs a perpendicular height. A trapezoid needs two parallel sides and the perpendicular distance between them. For an L-shape, enter the full outer rectangle and the missing corner.
Measured rooms are not certified living area
This tool sums the areas you enter. It does not account automatically for wall thickness, ceiling height, below-grade space, openings or appraisal exclusions. Assign every room to a floor; repeat rooms on another floor as separate entries.
Real-estate reporting requirements vary by purpose, jurisdiction and program. ANSI Z765 is a measurement standard, not a promise that all measured space qualifies as living area. For a listing, appraisal or transaction, ask the responsible professional which rules apply. See Fannie Mae’s appraisal guidance.
Formulas and exact conversion constants: methodology and sources.