SquareFootage exists to make measuring any space fast, precise, and completely private. Here's how our calculators work and why you can rely on them.
Last updated: July 2026
Every tool uses standard geometric and construction formulas — no approximations or hidden fudge factors.
All math runs in your browser. We never see, store, or transmit your measurements.
Real-time results, unit conversion, and material estimates built for real jobs — not just numbers.
Homeowners, contractors, and DIYers all get the same clear, free tools with no sign-up.
Square footage is simply area measured in feet. Every SquareFootage calculator applies the standard geometric formula for the shape you select, then converts the result into square feet, square meters, and square yards so it works for any project or region.
These are the exact formulas behind the tools — the same ones used across construction and mathematics:
| Rectangle / room | length × width |
|---|---|
| Triangle | ½ × base × height |
| Circle | π × radius² |
| Roof | footprint × pitch factor |
| Concrete volume | area × thickness ÷ 27 (cu yd) |
Results are rounded to two decimal places for readability. For irregular spaces, we recommend splitting the area into rectangles and triangles, calculating each, and adding the results. For materials, we apply industry-standard waste factors (typically 5–15%) so your estimates hold up on the job site.
Because all calculations run client-side in your browser, your measurements never leave your device — there are no accounts, no tracking of project data, and nothing stored on a server. We keep our formulas transparent so you can verify every result yourself.
Have a correction or a calculator you'd like us to add? Get in touch — we read every message.
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