Square Footage Calculator: Any Shape, Room & Cost
Measure rectangles, circles and irregular spaces. Add named areas, subtract cutouts and estimate material cost.
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.
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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.
Formulas and exact conversion constants: methodology and sources.
Square footage questions
How do I calculate square footage?
Measure the length and width in feet and multiply them. A 12 × 10 ft room is 120 sq ft. For an L-shaped space, split it into rectangles that do not overlap and add them together, or use the L-shape option above.
How do I handle inches?
Divide the inches by 12 and add them to the feet. 10 ft 6 in is 10.5 ft. The calculator does this for you when you enter feet and inches separately.
How many square feet is a 12 × 12 room?
144 sq ft, which is 16 sq yd.
How much extra material should I add?
Many flooring and tile installers add about 5–10% for cuts and breakage, and more for diagonal layouts. Check the product’s installation guide, then enter that percentage as extra. It changes the order quantity, not the measured area.
Do I measure to the wall or include closets?
For flooring or paint, measure the surface you are covering, inside the walls, and add closets as separate areas. Reported living area for a home sale follows different rules; see the house square footage calculator.
How many square feet are in an acre?
43,560 sq ft. Use the square feet to acres converter for land.