Floor Area Calculator
Total floor area of a room or a set of rooms.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Area = (Length × Width) + (second Length × second Width) − openings
Run the calculation to see each step with your own numbers.
A 12 ft × 14 ft living room with an L-shaped 4 ft × 6 ft nook.
Area 1 = 168 ft²; Area 2 = 24 ft²
Total = 192 ft² (21.3 yd²)
- Rectangular areas. For a room with more than two rectangles, or angled walls, split it and total the parts.
- The result is a net area — feed it into a material calculator, which adds its own waste allowance.
- How do I handle an L-shaped room?
- Split it into two rectangles, enter the first as Length × Width and the second in the 'second area' fields, and the calculator adds them. For more than two rectangles, run it in parts and total the results.
- Do I measure to the wall or the baseboard?
- To the finished wall surface, at floor level. Flooring runs wall-to-wall under the baseboard and shoe moulding, so measuring to the trim would leave you short.
- Square feet, square metres or square yards?
- The calculator shows all three. US hard flooring is usually priced per square foot; carpet is sometimes sold per square yard; metric products per square metre. Match the unit on your quote.
Geometry
Standard geometry (sum of rectangles). Unit conversions per NIST SP 811.
About the Floor Area Calculator
The Floor Area Calculator adds up the square footage of a room, or a pair of rectangular rooms, and deducts any area that will not be floored — a kitchen island, a hearth, a fixed cabinet run. The net figure it gives is the starting point for the Flooring and Tile calculators, which then add their own cut-waste allowance. For an L-shaped or multi-part room, split it into rectangles and total the parts.
What you enter
- Length
- Width
- Second area — length — Add an L-shaped extension. Leave 0 if not needed.
- Second area — width
- Area not floored — Deduct a kitchen island footprint, a hearth, a fixed cabinet run, etc. Leave 0 if none.
What you get back
- Floor Area — the exact result of the calculation.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Flooring Calculator — Flooring material (planks or boxes) for a room, including waste.
- Tile Calculator — Tiles and boxes needed for a floor or wall, including an allowance for cuts.
- Wall Square Footage Calculator — Wall area for one or more walls, with openings deducted.
Part of the Tile & Flooring calculators.