Enter the dimensions of up to three areas — rectangles, circles, or triangles — and get the total square footage, with conversions to square yards and meters. Add a cost per square foot for an instant project estimate.
How to measure square footage right
Measure at floor level with a tape or laser measure, wall to wall, and write down feet-and-inches as decimal feet (6 inches = 0.5 ft). For a simple rectangular room, one length and one width is all you need. Real rooms are rarely simple, though — the trick for an L-shape, a room with an alcove, or a kitchen wrapped around an island of cabinets is to break the space into rectangles and add them up. That's exactly what the three rows above are for: measure each chunk separately, and the calculator sums them.
The formulas
Rectangle = length × width · Triangle = ½ × base × height · Circle = π × (diameter ÷ 2)²
All dimensions are in feet, so results come out in square feet. For a circle, enter the diameter (the full distance across) in the first field and leave the second blank. One square yard is 9 sq ft, one square meter is about 10.76 sq ft, and an acre is 43,560 sq ft.
Worked example
An L-shaped living room: the main area is 18 × 12 ft (216 sq ft) and the alcove is 6 × 4 ft (24 sq ft), for a total of 240 sq ft — that's 26.67 sq yd or 22.3 sq m.
At $3.50 per sq ft for laminate, the material estimate is 240 × 3.50 = $840. With a 10% waste allowance you'd actually buy about 264 sq ft (~$924).
Buy 10% more than you measured
Flooring gets cut, and cuts create waste — boards trimmed at walls, tiles split around doorways, pattern matching, and the occasional miscut. The standard allowance is 10% extra (closer to 15% for diagonal layouts or complex tile patterns), and leftover boxes double as spares for future repairs. For scale, 240 sq ft is about a one-car garage; a standard parking space is ~160 sq ft, a tennis court is ~2,800 sq ft, and a football field is about 1.3 acres — handy references when a number on the screen needs a reality check.
Frequently asked questions
How do I calculate the square footage of a room?
Measure the length and width in feet at floor level and multiply them: a 12 × 14 room is 168 sq ft. Convert inches to decimal feet first (6 inches = 0.5 ft) so the multiplication comes out right.
How do I measure an L-shaped or irregular room?
Split it into rectangles, measure each one, and add the areas together — an 18 × 12 main area plus a 6 × 4 alcove is 216 + 24 = 240 sq ft. That's exactly what this calculator's three rows are for.
How much extra flooring should I buy for waste?
Add about 10% to your measured area to cover cuts, mistakes, and pattern matching — closer to 15% for diagonal layouts or intricate tile. Leftovers aren't wasted money: they're the spare boards you'll want for future repairs.
How many square feet are in a square yard, a square meter, and an acre?
A square yard is 9 sq ft, a square meter is about 10.76 sq ft, and an acre is 43,560 sq ft. Carpet is often quoted per square yard and land in acres, so the same area shows up in different units depending on what you're buying.
How do I estimate the cost of a flooring project?
Multiply the total square footage by the material price per square foot, then add your waste allowance: 240 sq ft at $3.50 is $840, or about $924 with 10% extra material. Installation labor is usually quoted per square foot too, so the same math works for the full job.