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Square footage calculator
Describe up to four shapes in feet: the total area shows in square feet, square yards and square meters, and in dollars if you add a price.
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Total area
168.0 sq ft
18.67 square yards · 15.61 square meters
| Area 1 | 168.0 sq ft |
| Area 2 | 0.0 sq ft |
One square yard is 9 square feet; one square meter is 10.764 square feet. For an L-shaped room, split it into two rectangles. How this is calculated.
A 12 by 14 foot room measures 168 square feet, which is 18.67 square yards or 15.61 square meters: multiply length by width in feet and you have it. Rooms and yards that are not rectangles break into simple shapes. An L-shaped living area of 20 by 12 feet with a 10 by 8 foot wing adds 240 and 80 for 320 square feet. A triangle is half of base times height, so a gable wall 24 feet wide and 6 feet tall above the eaves has 72 square feet. A round patio 12 feet across covers 113.1 square feet, pi times the radius squared, and a trapezoid lot is the average of its two parallel sides times the depth. The calculator takes up to four shapes at once, gives the total in all three units and, if you type a price per square foot for flooring, sod or paint labor, multiplies it out.
Measuring a room so the number holds up
Measure wall to wall at floor level, not along the baseboard tops, and write each dimension in feet with a decimal. Inches convert by dividing by 12: 7 inches is 0.58 feet, so a wall of 11 feet 7 inches is 11.58 feet. Rounding every dimension to the nearest half foot before multiplying can shift a large room by more than you think, so keep two decimals and round only the final answer. Closets with the same flooring count as part of the room; measure them as separate rectangles.
For any shape that is not a plain rectangle, sketch it on paper first and draw lines that cut it into rectangles, triangles and half circles. Each piece goes into one row of the calculator. The table shows the result for common shapes.
| Shape | Example | Square feet | Square yards | Square meters |
|---|---|---|---|---|
| Rectangle | 12 x 14 ft bedroom | 168.0 | 18.67 | 15.61 |
| Square | 12 x 12 ft room | 144.0 | 16.00 | 13.38 |
| L shape | 20 x 12 ft plus 10 x 8 ft | 320.0 | 35.56 | 29.73 |
| Triangle | Gable end, 24 ft base, 6 ft high | 72.0 | 8.00 | 6.69 |
| Circle | Patio 12 ft across | 113.1 | 12.57 | 10.51 |
| Trapezoid | Lot, 10 and 16 ft sides, 12 ft deep | 156.0 | 17.33 | 14.49 |
L shapes, bay windows and angled walls
An L-shaped room has two correct splits, one long rectangle plus one short, or two overlapping ones minus the overlap; the first is simpler. A bay window that pushes out 2 feet with a back of 8 feet and a face of 4 feet is a trapezoid of 12 square feet. A wall that meets another at an angle leaves a triangle you add or subtract. If you are pricing a floor, include the area under a fridge or a freestanding tub, but leave out kitchen cabinets and built-in islands that the flooring will not run under.
Turning square feet into material
Area is the starting point for almost every purchase in the house, and each material speaks its own unit. Carpet is often priced by the square yard, which is why the calculator shows it. Paint labels give coverage per gallon, around 350 square feet per coat in the default of the paint calculator and 400 to 450 on the Benjamin Moore Regal Select data sheet; two coats on the 12 by 14 foot ceiling would take 0.96 gallons. Drywall sheets cover 32 square feet each in the 4 by 8 size listed by USG, so the 12 by 14 foot ceiling needs 6 sheets before any allowance. Mulch is bought by the cubic yard: Clemson Extension puts one yard at 324 square feet an inch deep, so the round patio area as a planting bed would take 1.05 cubic yards at 3 inches. Roofing is sold by the square of 100 square feet, and the Owens Corning specification rates one square of three-tab shingles at 100 square feet of coverage; the roofing calculator adds the pitch.
Living area is a different number
The square footage on a listing or an appraisal follows its own rules about stairs, attics, ceiling height and finished space, and it is often measured from the outside of the walls, so it rarely matches the sum of the rooms you measure inside. Use your own measurements for materials and contractor quotes; use the listed living area when a source like the roof replacement cost page groups prices by house size.
Pricing a job by the square foot
Flooring installers, sod suppliers, painters and concrete finishers often quote per square foot. Type that price into the optional field and the calculator multiplies it by the total. Add a margin for cuts and pattern matching on flooring and tile before you buy: the waste depends on the layout and the product, and the installer or the box label gives the figure that fits your floor.