Square Footage Calculator
Add up the area of rooms and shapes in sq ft and m², with materials cost.
Measure Once, Order The Right Amount
Add each room or area, choose its shape — rectangle, L-shape, circle, triangle or trapezoid — and type its measurements in feet, inches, yards, metres or centimetres. The total area appears in square feet, square metres and square yards as you type.
For flooring, tiling, carpet, paint or turf, set a waste allowance and the price per square foot, and the calculator gives the amount to order and what it will cost. Irregular rooms are simply split into shapes and added together.
Key features
- Five shapes, including L-shaped rooms.
- Any unit in — ft, in, yd, m, cm.
- Square feet, metres and yards out.
- Waste allowance for cuts and pattern matching.
- Material cost from your price per square foot.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Square Footage Calculator
- Choose the unit you measured in
Every area uses the same unit. - Add each area and pick its shape
Split irregular rooms into simple shapes. - Enter the measurements
Each area’s result shows alongside it. - Set waste and price
Order the “with waste” figure.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Calculators |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
How do I calculate square footage?
For a rectangle, multiply length by width in feet: a 12 × 15 ft room is 180 sq ft. For other shapes, split the space into rectangles, triangles and circles and add their areas together.
How much extra flooring should I buy?
Around 5–10% for straight-laid planks or carpet, 10–15% for tiles, and 15–20% for diagonal or herringbone patterns and rooms with many corners.
How do I convert square feet to square metres?
Divide by 10.764. One square metre is 10.764 square feet; one square yard is exactly 9 square feet.
How do I measure an L-shaped room?
Measure the full length and full width as if it were a rectangle, then the size of the missing corner. The L-shape option subtracts the corner for you.
Should I measure in inches or feet?
Either — choose the unit you measured in and the calculator converts. Measuring to the nearest inch or centimetre is precise enough for ordering materials. Measure wall to wall at floor level, and take two readings in older rooms, which are rarely perfectly square; use the larger one.