Square Footage Calculator
Measure up any space. Enter the length and width to get the area in square feet and square yards, the perimeter, and—if you add a price—an estimated material cost.
Your project
Estimate
180ft²
Square footage
- Square yards
- 20yd²
- Perimeter
- 54ft
- Estimated cost
- $0.00
Estimates are guidance only and exclude tax, labor, and site conditions unless stated. Confirm with a local pro.
How it's calculated
No black boxes — here is the exact math behind your estimate, so you can check it or adapt it for your own quote.
- 1
Square feet = length × width - 2
Square yards = square feet ÷ 9 - 3
Perimeter = 2 × (length + width) - 4
Cost = square feet × price per ft²
Worked example
A 15 ft × 12 ft room.
Inputs
- Length
- 15 ft
- Width
- 12 ft
- Price per ft² (optional)
- 0 $/ft²
Result
- Square footage
- 180 ft²
- Square yards
- 20 yd²
- Perimeter
- 54 ft
- Estimated cost
- $0.00
Tools & materials for this project
As an Amazon Associate we may earn from qualifying purchases, at no extra cost to you.
- Laser measure Measure rooms fast and accurately.
- Tape measure A 25 ft tape for everyday measuring.
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Frequently asked questions
How do I calculate square footage?
Multiply the length by the width, both in feet. A 15 ft × 12 ft room is 180 square feet. For an L-shaped or irregular space, split it into rectangles, find each area, and add them together.
How many square feet are in a square yard?
One square yard equals 9 square feet (3 ft × 3 ft). To convert square feet to square yards — useful for carpet — divide the square footage by 9.
How do I find square footage from inches?
Convert each measurement to feet first by dividing inches by 12, then multiply length × width. Alternatively, multiply the dimensions in inches and divide the result by 144.