Square Footage Calculator

How to use the Square Footage Calculator

1. Pick US or Metric, then choose the unit you measured in (feet, inches, yards, meters or centimeters).
2. Choose a shape for the first area and enter its measurements. Each row shows its own area as you type.
3. Click ＋ Add another area for each extra room, closet or section. Set a row to Subtract for cut-outs like a kitchen island or fireplace hearth.
4. Read the total in square feet, square yards, square meters, acres and hectares.
5. Optionally type your own price per square foot (or per m²) to get a rough cost.

How it works

Area is length times width for a rectangle. The other shapes use the standard geometry formulas: a circle is π × (diameter ÷ 2)², a triangle is ½ × base × height, and a trapezoid is ½ × (side a + side b) × height, where a and b are the two parallel sides and the height is measured straight across between them. The L-shape option simply adds two rectangles, so measure the room as two non-overlapping boxes.

Every row is converted to square feet internally using exact definitions (1 foot = 0.3048 m, 1 yard = 3 feet), then shown in the other units: 9 sq ft per sq yd, 0.09290304 m² per sq ft, 43,560 sq ft per acre and 10,000 m² per hectare.

Example: a 12 ft × 14 ft bedroom (168 sq ft) plus a 5 ft × 6 ft closet (30 sq ft) is 198 sq ft, which is 22 sq yd or about 18.39 m². At a quoted $3.25 per sq ft, materials would be about $643.50 before waste.

The result is the net floor or wall area. For flooring, tile, sod or paint you normally buy 5–15% extra for cuts and mistakes, so use the dedicated calculators linked below when you need material counts.

Frequently asked questions

How do I measure an irregular room?
Split it into simple shapes that don't overlap, such as a large rectangle plus a smaller one, or a rectangle plus a triangle. Add a row for each piece. For a bump-out you don't want counted, add it as a separate row and set it to Subtract.

Can I mix feet and inches?
Pick inches in the "Measure in" list if you measured with a tape in inches. For a mix like 12 ft 6 in, type 12.5 feet (6 inches is half a foot) or convert everything to inches first (150 in).

How many square feet are in an acre?
One acre is exactly 43,560 square feet, or about 4,046.86 square meters. A hectare is 10,000 m², about 2.471 acres.

Does this include waste for flooring?
No. This calculator gives the measured area only. Our Tile & Flooring Calculator adds a waste allowance and counts tiles and boxes.

Why is my circle area different from my estimate?
Make sure you entered the full diameter (edge to edge through the center), not the radius. The area of a 10 ft circle is about 78.54 sq ft, while a 10 ft radius gives about 314.16 sq ft.