Square Footage Calculator
Width × length in feet to square feet
"Square Footage Calculator" Calculator
Square Footage: the Formula, the Steps and the Sizes People Look Up
How to calculate square footage
Square footage is area measured in square feet — the number of one-foot squares that fit inside a shape. For anything rectangular that is a single multiplication:
square feet = width (ft) × length (ft)
The formula is a product rather than a sum because a square foot is itself a product: a square one foot on each side. Lay those squares out in rows and a rectangle 12 ft by 14 ft holds 12 of them in every row and 14 rows — 168 in total. That is also why the two sides can be swapped: 12 × 14 and 14 × 12 are the same number.
Step by step
- Measure both sides in feet. Measure at floor level, along the longest straight run of each side.
- Turn inches into a decimal. Divide the inches by 12 and add them on — 12 ft 6 in becomes 12.5 ft, 10 ft 3 in becomes 10.25 ft.
- Multiply. Width × length gives the square footage.
- Add up the parts. If the shape is not a plain rectangle, split it into rectangles, do each one separately and add the results.
Common sizes and their square footage
| Size | Square feet | Typically |
|---|---|---|
| 3 × 5 feet | 15 square feet | area rug |
| 4 × 8 feet | 32 square feet | plywood sheet |
| 10 × 10 feet | 100 square feet | small bedroom |
| 10 × 12 feet | 120 square feet | bedroom |
| 12 × 12 feet | 144 square feet | bedroom, single garage bay |
| 12 × 14 feet | 168 square feet | bedroom, living room |
| 12 × 16 feet | 192 square feet | living room |
| 14 × 16 feet | 224 square feet | master bedroom |
| 16 × 20 feet | 320 square feet | large living room |
| 20 × 20 feet | 400 square feet | two-car garage |
| 24 × 24 feet | 576 square feet | large garage, workshop |
| 20 × 30 feet | 600 square feet | shop floor, small barn |
What people measure in square feet
- Flooring and carpet: laminate, tile and carpet are all priced per square foot, and buying about 10% extra covers cuts and pattern matching.
- Sheet material: a standard plywood sheet is 4 × 8 ft, so it covers 32 square feet — the quickest way to work out how many sheets a job takes.
- Paint and coatings: coverage is quoted in square feet per gallon or per litre.
- Land, lawns and turf: yards, garden beds and sod all get quoted by the square foot.
- Rent and property listings: in the United States and Canada, homes and offices are advertised by their square footage.
Where this formula stops working
- The shape must be rectangular. For an L-shaped room, split it into rectangles first. For a circle use π × radius², for a triangle half of base × height.
- Floor area is not wall area. A wall is height × length, and four walls of a 12 × 14 ft room come to far more than 168 square feet.
- A sloped surface covers more than its footprint. A pitched roof needs its own slope factor.
- Listed square footage may be measured differently. Property listings sometimes measure to the outside of the walls, so a floor you measure yourself will come out smaller.
Square feet in other units
One square foot is 0.092903 square meters, one ninth of a square yard, and one 43,560th of an acre. Every result page prints the metric and yard equivalents alongside the answer, and the site has dedicated converters for square feet to square meters and square feet to acres if that is the conversion you came for.
Note: the foot is the everyday building unit in the United States, Canada and the United Kingdom. Most of the world quotes floor area in square meters — the numbers here convert cleanly either way.
See Also
- Square Feet to Square Meters (Sq Ft to Sq M) - Convert Square Feet to Square Meters
- Square Meters to Square Feet (Sq M to Sq Ft) - Convert Square Meters to Square Feet
- Square Inches to Square Centimeters - Convert Square Inches to Square Centimeters
- Square Centimeters to Square Inches - Convert Square Centimeters to Square Inches
- Square Feet to Acres - Convert Square Feet to Acres
- Acres to Square Feet - Convert Acres to Square Feet
- Square Kilometers to Square Miles - Convert Square Kilometers to Square Miles
- Square Miles to Square Kilometers - Convert Square Miles to Square Kilometers
- Acres to Hectares - Convert Acres to Hectares
- Hectares to Acres - Convert Hectares to Acres
- Square Meters to Hectares - Convert Square Meters to Hectares
- Hectares to Square Meters - Convert Hectares to Square Meters
About "Square Footage Calculator" Calculator
This calculator works out the square footage of a rectangle from its two sides in feet. For example, it can help you find out how many square feet is 12 × 14 ft? (The answer is: 168 square feet). Enter the width (e.g. 12 ft) and the length (e.g. 14 ft) in feet — half-feet and decimals such as 10.5 are accepted.
FAQ
How do you calculate square footage?
Measure the two sides of the rectangle in feet and multiply them: square feet = width × length. A 12 ft by 14 ft rectangle is 12 × 14 = 168 square feet.
What if the measurement is in feet and inches?
Turn the inches into a fraction of a foot before multiplying: divide the inches by 12 and add them to the feet. 12 ft 6 in is 12.5 ft, so 12 ft 6 in by 14 ft is 12.5 × 14 = 175 square feet.
Does the order of the two sides matter?
No. Multiplication is commutative, so 12 × 14 and 14 × 12 give the same 168 square feet. The pages here always list the shorter side first.
How do you find the square footage of a room that is not rectangular?
Split it into rectangles, work out the square footage of each one separately and add the results. An L-shaped room is two rectangles; a closet or an alcove is one more.
Is square footage the same as floor area?
For a flat floor, yes — it is the same measurement. Wall area, roof area and usable area are different figures: walls are height × length, and a sloped roof covers more surface than its footprint.