Square Footage Calculator

Find the square footage of a rectangle, circle, triangle or trapezoid from measurements in feet, inches, yards, meters or centimeters, see it in square yards, square meters and acres, and price it by the square foot. Your inputs stay in your browser.

Your measurements

Shape

The distance across the circle through its center.

Measured at a right angle to the base.

One of the two parallel sides.

The other parallel side.

The distance between the parallel sides.

Optional

For example, three bedrooms of the same size.

168 sq ft (15.61 m²). See full results

Example: a 12 × 14 ft room. Choose a shape and enter your measurements to update.

Your area

Square feet
168 sq ft
Total area
Square meters
15.61 m²
1 sq ft = 0.0929 m²

The same area in other units

UnitArea
Square feet 168
Square inches 24,192
Square yards 18.67
Square meters 15.61
Acres 0.0039

How to calculate square footage

For a rectangle or square, multiply the length by the width in feet: 12 ft × 14 ft = 168 sq ft.

Square feet = length (ft) × width (ft)

Irregular rooms: split the floor into rectangles, work out each one and add them. An L-shaped room made of a 12 × 14 ft area and a 6 × 8 ft nook is 168 + 48 = 216 sq ft. To leave out something like a kitchen island, subtract its area instead.

Other shapes

  • Circle: π × (diameter ÷ 2)². A 10 ft circle is 78.54 sq ft.
  • Triangle: base × height ÷ 2. A triangle 8 ft across and 6 ft high is 24 sq ft.
  • Trapezoid (two parallel sides): (side a + side b) ÷ 2 × height. Sides of 10 and 14 ft, 8 ft apart, make 96 sq ft.

Measuring in inches or meters

Convert before you multiply, or convert the answer: there are 12 inches in a foot, so 144 square inches in a square foot (NIST: tables of units of measurement). A floor measured as 144 × 168 inches is 24,192 sq in ÷ 144 = 168 sq ft. A foot is exactly 0.3048 m, so a 4 × 5 m room is 20 m² or 215.28 sq ft.

Square feet in other units

Square feetSquare yardsSquare metersAcres
100 11.119.290.0023
250 27.7823.230.0057
500 55.5646.450.0115
1,000 111.1192.90.023
1,500 166.67139.350.0344
2,000 222.22185.810.0459
2,500 277.78232.260.0574
5,000 555.56464.520.1148
10,000 1,111.11929.030.2296
43,560 4,8404,046.861

Square footage of a house

This calculator gives the geometric area of what you measure. The square footage in a listing or an appraisal follows measurement rules about what counts, such as whether garages, unfinished basements, stairs or areas with low ceilings are included, so it can differ from the sum of your room measurements.

Methodology and testing

Dimensions are converted to feet first (1 ft = 12 in = ⅓ yd = 0.3048 m). Square yards = sq ft ÷ 9; square meters = sq ft × 0.09290304; acres = sq ft ÷ 43,560. Automated tests check each shape against hand-worked examples, that the same area entered in different units gives the same square footage, and the conversions. How we build and test calculators.

Sources

  • Flooring Calculator

    Square footage for several rooms, waste by layout, boxes from carton coverage, leftover and cost.

  • Drywall Calculator

    Wall and ceiling area less doors and windows, waste, and sheets for 4×8, 4×10 and 4×12 ft sizes, with cost.

  • Concrete Calculator

    Cubic yards and bags of concrete for slabs, footings and post holes, with a waste allowance and a bags-vs-ready-mix cost check.

  • Home Affordability Calculator

    Maximum home price from income, debts and down payment, the debt-to-income limit that binds, and the price at other rates.

  • BTU Calculator

    Room air conditioner size in BTU per hour from the ENERGY STAR chart, adjusted for sun, shade, people and kitchens.