Square Footage Calculator
Total square footage across rooms — with square meters and cost per square foot
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Quick summary
Square footage is length × width for each rectangular space, summed. A 20×15 living room (300 sq ft) plus a 12×12 bedroom (144) totals 444 sq ft — about 41 m². For L-shaped rooms, split into rectangles and add each as a row. The cost field turns the total into a quick estimate for flooring, cleaning, painting quotes, or rent comparisons.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Enter the inputs requested by the calculator.
- Choose the units or options that match your situation and review the assumptions.
- Run or update the calculation to see the result.
- Review the result, breakdown, and formulas shown on the page.
- Check the inputs, units, dates, and limitations before saving or sharing the result.
Frequently asked questions
How do I calculate square feet?
Multiply length by width in feet: a 12 ft by 14 ft room is 168 sq ft. Measure at floor level along the walls, and for irregular shapes, break the space into rectangles and sum them — that's exactly what the multi-room rows here do.
What counts in a home's listed square footage?
Finished, heated, above-grade living area — measured from exterior walls in most US conventions (ANSI standard). Garages, unfinished basements, and open porches don't count, which is why your room-by-room interior total will run smaller than the listing number.
How do I convert square feet to square meters?
Multiply by 0.0929 (or divide by 10.764). 444 sq ft ≈ 41.2 m². The calculator shows both automatically.
How do I measure a room with alcoves or an L-shape?
Divide it into non-overlapping rectangles at the corners, measure each, and add them as separate rows. A 20×15 room with a 4×3 alcove is 300 + 12 = 312 sq ft.
Key terms
- ANSI Standard
- The common US convention for measuring home area — finished, heated space measured to exterior walls.
- Gross vs Usable Area
- Commercial leases distinguish total footprint from the space you can actually occupy — residential rarely does.
- Cost per Square Foot
- Total ÷ area — the standard unit for comparing construction, flooring, rent, and home prices.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.