Measure the space
Measure length and width with a tape measure. Include alcoves that belong to the surface you are covering. Record inches as well as feet when you need a closer estimate.
ROOMS · FLOORING · MATERIALS
Square Footage Calculator
Calculate the area of a room, combine multiple spaces, and estimate how much material you need. Enter feet, feet and inches, or metric measurements to get square feet, square meters, and square yards.
Multiple rooms & cutouts5 area shapesAll calculations in your browser
MEASURE ONCE, CALCULATE CLEARLY
How to calculate square footage
Square footage measures a flat surface. For a rectangular room, multiply its length by its width after converting both measurements to feet.
Choose the shape
Use a rectangle for most rooms. Select a circle, triangle, square, or L-shaped area when appropriate. Split more complicated layouts into separate, non-overlapping sections.
Add or subtract areas
Add rooms for a total, or choose “Subtract area” for an uncovered section. Deduct only surfaces that should be excluded from your material estimate.
WORKED EXAMPLE
A 12 ft × 10 ft room
The room has an area of 120 sq ft. A 10% material allowance adds 12 sq ft, giving 132 sq ft to cover. At 3.50 per square foot, the estimated material cost is 462.00 in the currency of your quote.
12 × 10120 sq ft120 × 1.10 = 132 sq ft with allowance
Square footage formulas for different shapes
These are the formulas used by this calculator. All dimensions are converted to feet before the area is calculated. For a triangle, measure the perpendicular height rather than the sloping side.
| Shape | Formula | Measurements |
|---|---|---|
| Rectangle | length × width | Two perpendicular sides |
| Square | side × side | One side |
| Circle | π × (diameter ÷ 2)² | Diameter through the center |
| Triangle | base × height ÷ 2 | Base and perpendicular height |
| L-shaped area | outer length × outer width − cutout length × cutout width | Outer rectangle and rectangular corner cutout |
Feet and inches to square feet
Convert the inches into a fraction of a foot before multiplying. For example, 10 ft 6 in is 10.5 ft. A room measuring 10 ft 6 in by 8 ft 4 in has an area of 87.5 sq ft.
Select “Feet + inches” to enter the two parts separately. Do not enter 10.6 to mean 10 ft 6 in: 10.6 decimal feet is 10 ft 7.2 in.
Multiple rooms and irregular layouts
Calculate every section and add the areas together. A 12 × 10 ft room and a 6 × 4 ft hallway total 144 sq ft. Avoid counting an overlapping section twice.
For an L-shaped room with a 15 × 12 ft outer rectangle and a 5 × 4 ft corner cutout, the area is 180 − 20 = 160 sq ft. A cutout must fit within the outer rectangle.
Flooring, tile, and material allowance
The measured area and the material order are different quantities. The calculator applies your allowance using net area × (1 + extra percentage ÷ 100). The preset 10% is an editable starting point, not a requirement for every project.
Follow the product’s installation guidance for waste, pattern matching, and spare material. If flooring comes in boxes covering 20 sq ft, a 132 sq ft estimate needs 7 boxes because 132 ÷ 20 = 6.6 and partial boxes may not be sold.
Square feet, square meters, and square yards
One square foot equals 144 square inches or 0.09290304 square meters. One square yard equals 9 square feet. The calculator shows all three main area units from the same unrounded result.
Area is different from volume. For concrete, soil, or another material sold by cubic volume, you also need the depth. Square footage alone does not tell you the number of cubic yards to order.
Square footage calculator FAQs
How many square feet are in a 10 × 12 room?
A rectangular room measuring 10 feet by 12 feet has an area of 120 square feet. This is the measured area before adding any allowance for material cuts or waste.
Can I enter measurements in meters?
Yes. Select meters and enter your dimensions. A 3 × 4 meter room has an area of 12 square meters, or approximately 129.17 square feet. Changing units converts measurements that are already entered.
How do I calculate the square footage of a wall?
Multiply the wall’s width by its height. Use a rectangle for each wall and add the areas. Subtract doors or windows when the surface estimate should exclude them. Paint coverage also depends on coats and the product’s stated coverage.
Can I calculate the area of a whole house?
You can add the measured area of each room or floor. Do not count the same space twice. This tool gives a geometric area estimate; whether a space counts as reportable living area depends on the measurement standard and local rules used for the listing.
Does the result include waste or extra flooring?
The net area does not include extra material. “Material to cover” adds the percentage entered in the material estimate section. Set that percentage to zero to use the measured area alone.
Why can the displayed room areas differ slightly from the total?
The total is calculated from unrounded room areas. Each displayed value is rounded to two decimal places, so adding the displayed values can sometimes produce a small rounding difference.
Are my measurements uploaded?
This calculator does not send measurements to an external calculation service or save them in browser storage. Calculations run locally in your browser. Site-wide analytics, if enabled by the website owner, operate separately.