Square Footage Calculator
Use this free square footage calculator to add rooms and get instant totals in square feet, square yards, and square meters.
Calculate Area in Square Feet
Room and Area Measurements
sq ft
Subtract the corner cutout (a × b) from the overall rectangle (L × W).
Measure straight across the center of the circle.
Height is perpendicular to the base, not the slanted side.
Numbers use the selected unit. Feet + inches: 12'6" or 12 ft 6 in.
Total Area
Square feet (sq ft)
- Square yards (sq yd)
- Square meters (m²)
Enter dimensions to see your total.
Results are rounded to 2 decimal places.
What Is Square Footage?
Square footage measures the area of a surface in square feet. One square foot is a square with sides that each measure one foot. The labels square feet, sq ft, and ft² all describe the same unit. Area tells you how much surface you have, rather than how far it is around the edges.
You can use square footage when comparing room sizes, planning new flooring, measuring a wall for paint, or ordering grass for a yard. Measure the surface you actually want to cover: a floor uses room length and width, while a wall uses its length and height. A measurement in linear feet alone does not tell you the area.
How to Calculate Square Feet
Measure Length and Width
Measure each dimension with a tape measure and record the unit. For a rectangular floor, measure the length and width between its boundaries. Convert both measurements to feet before multiplying. If your tape reads feet and inches, divide the inches by 12 and add them to the feet. For example, 6 inches equals 0.5 feet, not 0.6 feet.
Rectangle area in square feet = length in feet × width in feet
Area Formulas for Common Shapes
- Rectangle: length × width.
- Square: side × side.
- L-shaped: overall length × overall width − cutout length × cutout width.
- Circle: π × (diameter ÷ 2)².
- Triangle: base × perpendicular height ÷ 2.
For a triangle, measure the height at a right angle to the base. For an L-shaped room, imagine filling in the missing corner to make a complete rectangle, then subtract that corner. Use the diagram in the calculator to match each measurement to its field.
Three Worked Examples
- Square bedroom: a room 12 feet long and 12 feet wide covers 12 × 12 = 144 sq ft.
- Feet and inches: a room measuring 12 feet 6 inches by 10 feet covers (12 + 6 ÷ 12) × 10 = 125 sq ft.
- L-shaped floor: a 20 × 15 foot outer rectangle with an 8 × 5 foot corner missing covers 300 − 40 = 260 sq ft.
Square Footage by Room Size (sq ft)
Use this table for a quick check of common rectangular room dimensions. All lengths and widths are in feet. A 10 × 12 room has the same area as a 12 × 10 room; swapping length and width does not change the result.
| Room size | Area (sq ft) |
|---|---|
| 10 × 10 ft | 100 |
| 10 × 12 ft | 120 |
| 12 × 12 ft | 144 |
| 12 × 15 ft | 180 |
| 15 × 20 ft | 300 |
| 20 × 20 ft | 400 |
These figures assume a complete rectangle. Measure closets, alcoves, or adjoining sections separately when they are part of the surface you need. Do not count a closet twice if its area is already included in the main room measurements.
Calculate Square Footage per Room
Add Multiple Rooms
For a project spanning several rooms, keep each room in its own row. Select Add another area, choose a shape and input unit, and enter the dimensions. The square footage calculator adds the completed areas automatically. You can remove any row without changing the other rooms.
A 144 sq ft bedroom, a 240 sq ft living room, and a 48 sq ft hallway give a total of 432 sq ft. Check the area subtotals before using the total to order materials. Incomplete or invalid rows are excluded and identified next to the total.
Measure Irregular Rooms and Wall Areas
Divide complicated floors into simple shapes that do not overlap. If you have already measured an entire L-shaped room, do not add one of its legs again. For walls, enter each wall's length and height as a rectangle. To find net paintable area, separately subtract doors and windows from the gross wall total; added rows here always increase the total.
Convert Square Feet to Square Yards and Square Meters
Square Feet to Square Yards
One yard equals three feet, so one square yard measures 3 × 3 feet and contains nine square feet. Divide a square-foot measurement by nine to get square yards. For example, 144 sq ft ÷ 9 = 16 sq yd. This is useful when carpet or turf is quoted by the square yard; always check the seller's stated unit.
Square Feet to Square Meters
Multiply square feet by 0.09290304 to convert to square meters. An area of 144 sq ft is approximately 13.38 m². The calculator displays all three units together. Its conversions use the unrounded area, so small rounding differences in individual room displays do not accumulate in the total.
Estimate Material Cost from Square Footage
Multiply Area by Price per Unit
Once you know the area, multiply it by a quoted material price using the same area unit. At an example price of $3 per sq ft, material for a 144 sq ft room would cost $432. This is an illustrative material subtotal, not a current price quote or installation estimate.
Estimated material cost = area × price per matching area unit
Match Units and Allow for Project Extras
If a price is per square yard, use the square-yard result. Check package coverage and allow for cuts or pattern matching based on the product and layout. Purchased quantities may exceed measured area. Consider labor, delivery, and taxes separately when preparing a full project budget.
Square Footage Calculator FAQ
How do I calculate square footage of a room?
For a rectangular room, measure the length and width in feet and multiply them. A room measuring 10 feet by 12 feet has an area of 120 square feet. For an irregular room, divide the floor into nonoverlapping shapes, calculate each area, and add the results.
How many square feet is a 12x12 room?
A 12x12 room is 144 square feet when both dimensions are measured in feet: 12 × 12 = 144. That is also 16 square yards or approximately 13.38 square meters. This assumes a complete square floor, without any extra alcoves or missing sections.
How do I calculate square footage with feet and inches?
Divide the inches by 12, then add that number to the feet before multiplying your dimensions. For example, 12 feet 6 inches becomes 12.5 feet. You can also enter 12'6" or 12 ft 6 in directly into this calculator; both represent the same length.
How do I calculate the total square footage of multiple rooms?
Calculate each room separately and add its area to the others. Select Add another area for every room, hallway, or other section. Each row can use its own shape and measurement unit. The total updates as you type, and any incomplete areas are clearly marked as not included.
How do I calculate the square footage of an L-shaped room?
Measure the full outer length and width as though the missing corner were filled in. Multiply those measurements, then subtract the missing rectangle's length times width. In L-shaped mode, enter the two overall dimensions and the two cutout dimensions. The cutout must be smaller than the corresponding outer dimensions.
How do I convert square feet to square yards?
Divide the area in square feet by 9. For example, 180 square feet equals 20 square yards. Divide by 9 rather than 3 because area has two dimensions: a square measuring 1 yard on each side measures 3 feet by 3 feet, or 9 square feet.
How do I calculate flooring cost from square footage?
Multiply the area by the material price per square foot. At an example price of $3 per square foot, 144 square feet costs $432 before extras. Match the area unit to the quoted price, and account separately for package quantities, cutting waste, installation, delivery, and taxes.
What is the difference between square feet and linear feet?
Square feet measure area, while linear feet measure length. A strip of flooring that is 10 feet long and 2 feet wide covers 20 square feet but measures 10 linear feet along its length. To convert a length into an area, you must also know the width.