Square Footage Calculator
Add up as many areas as your project has — rooms, patios, garden beds — in whatever unit your tape measure uses. Subtract cut-outs, add a waste allowance, and see the material cost before you buy anything.
| Areas added | — |
| Cut-outs subtracted | — |
| Net area | — |
| In square yards | — |
| In square meters | — |
| In acres | — |
| Area incl. waste | — |
| Estimated material cost | — |
Everything is calculated locally in your browser — no measurements are sent anywhere. Mixed units are converted exactly (1 ft = 0.3048 m, 1 sq yd = 9 sq ft, 1 acre = 43,560 sq ft).
Contractors: turn measurements into money
Measured the job? Two companion tools pick up where this one stops:
ProfitBid — turn measurements into a bid: build a priced quote with your margin built in, instead of guessing a number on the spot.
RemodelCostCalc — estimate the remodel: kitchen and bathroom cost calculators that sanity-check your square footage against real project budgets.
How the calculator works
Each row is one area. Pick its shape, type the dimensions in any of feet, inches, yards, meters or centimeters — rows can mix units freely, because every dimension is converted to feet first (1 ft = 0.3048 m exactly). Tick Cut-out on a row to subtract it instead: kitchen islands, hearths, stair openings and the patch of lawn the shed sits on.
| Shape | Measure | Formula |
|---|---|---|
| Rectangle | Length × Width | L × W |
| Circle | Diameter | π × (d ÷ 2)² |
| Triangle | Base × Height | ½ × b × h |
| Trapezoid | Two parallel sides × Height | (a + b) ÷ 2 × h |
The totals convert the net area into square yards (÷ 9), square meters (× 0.09290304) and acres (÷ 43,560). The waste percentage inflates the area before pricing — 10% is the usual allowance for straight flooring layouts, 15% or more for diagonal and herringbone patterns. Cost is simply area incl. waste × your price per square foot.
Worked example
A living room of 14 × 12 ft (168 sq ft) plus a hallway of 4 × 8 ft (32 sq ft) totals 200 sq ft — that is the preset loaded in the calculator above. In other units: 22.22 sq yd and 18.58 m². Add 10% waste and you should buy for 220 sq ft; at $4.50 per sq ft the material estimate is $990.00. Try it: the waste and price fields are right there.
Common room sizes
More calculators
Frequently asked questions
How do I calculate square footage?
For a rectangle, multiply length by width in feet: a 12 ft × 10 ft room is 120 sq ft. For anything that is not a rectangle, split it into rectangles (and triangles or circles where needed), work out each piece, and add them — that is exactly what the rows above do.
How do I measure an L-shaped room?
Draw the L as two rectangles, measure each, and add the two areas. Example: a 20 × 12 ft section (240 sq ft) plus a 10 × 8 ft section (80 sq ft) is 320 sq ft. See the measuring guide for a diagram in words and rounding rules.
How many square feet are in a square yard or an acre?
One square yard is exactly 9 sq ft. One acre is exactly 43,560 sq ft. One square foot is 0.09290304 sq m, and one square meter is about 10.7639 sq ft.
How much extra material should I buy for waste?
5–10% for straight flooring and simple tiling, 15%+ for diagonal or patterned layouts, and around 10% for carpet and turf. The waste field applies the allowance to the area before pricing, which is how suppliers quote it.
Can I mix feet, inches and meters?
Yes — each row has its own unit. A wall measured as 380 cm and a floor measured as 12 ft 6 in (enter 12.5 ft, or 150 in) can live in the same project; everything is converted to feet before the math.
Is any of this uploaded or saved?
No. The calculator runs entirely in your browser on this page. There is no account and nothing you type is sent to a server. See the privacy page.