About the Square Footage Calculator
A square footage calculator finds the floor area of a room or space. It is the starting point for every flooring, paint, tile, and carpet estimate, and the basis for property measurement and rental pricing.
The formula
Square footage = length (ft) · width (ft)Both dimensions in feet give an area in square feet. For irregular spaces, divide into rectangles, calculate each, and add the results.
How to use this calculator
- 1Enter your Length (ft). The field starts at
15, which you can overwrite. - 2Enter your Width (ft). The field starts at
12, which you can overwrite. - 3Read the result straight away — it recalculates as you type, so there is no button to press. Use Share to copy a link that reopens the page with your exact numbers filled in.
Worked example
| Input | Value |
|---|---|
| Length (ft) | 15 |
| Width (ft) | 12 |
Result
Square Feet: 180.00 sq ft
Square Meters: 16.72 m²
Square Yards: 20.00 sq yd
Acres: 0.004132 acres
Perimeter: 54.00 ft
Those are the values the page loads with, so you can reproduce this result yourself and then change one field at a time to see what drives the outcome.
Understanding your result
The measurement itself is simple; the complications are all in what to include. Closets, alcoves, bay windows, and the area under stairs may or may not count depending on the standard being applied. Real estate listings, tax assessments, and lease agreements each use their own conventions, which is why the same house can be advertised at several different square footages.
For material ordering, subtract what you are not covering and add for waste. Cabinets, kitchen islands, and built-in fixtures reduce the area needing flooring, while cuts and pattern matching increase what you must buy — typically 5 to 10 percent, and up to 15 for diagonal layouts.
Things worth knowing
- Break irregular rooms into rectangles and triangles, then add the areas.
- Add 5 to 10 percent for flooring waste, and 15 percent for diagonal or patterned installations.
- Subtract permanent fixtures — cabinets, islands, hearths — that will not be floored.
- One square metre is 10.764 square feet. Getting this conversion wrong is a common ordering error.
- Measure at the widest points and note ceiling height separately if you are also estimating paint.
Frequently asked questions
How do I calculate square footage?+
Multiply length by width in feet. A room 15 by 12 feet is 180 square feet. For irregular shapes, split into rectangles and add the areas together.
How much flooring should I buy?+
The calculated area plus 5 to 10 percent for cuts and waste, rising to 15 percent for diagonal layouts or patterns needing alignment. Buying short mid-job risks a dye-lot mismatch.
Does square footage include closets?+
It depends on the standard. Real estate listings usually include closets as living space; some tax assessments and lease measurements do not. This is why quoted figures for the same property differ.
How do I convert square feet to square metres?+
Divide by 10.764. A 1,000 square foot space is about 92.9 square metres. Remember the conversion is squared, so it is not the same as the linear factor.