Floor Area Calculator
Floor area = length × width for each rectangle, added together, minus anything that won't be floored. A 12 × 14 ft room with a 4 × 6 ft nook is 168 + 24 = 192 ft² (21.3 yd²). It adds no waste; the Flooring Calculator and Tile Calculator add their own cut allowance.
How it's calculated: Area = (length × width) + (second length × second width) − area not floored.
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.
- How many square feet is a 12x14 room?
- 168 ft²: 12 ft × 14 ft. Add an alcove or nook as a second rectangle — a 4 × 6 ft nook makes the room 192 ft².
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.
Related articles
- Roof Area vs Floor Area: Why Are They Different? — Floor area is a flat measurement; roof area accounts for the slope. On anything but a flat roof, the two numbers are never equal.
Part of the Tile & Flooring calculators.