Square Footage Calculator
Add up rooms in feet and inches, subtract islands or closets, and get your total with waste and cost.
Related square footage calculators
The basics
How to calculate square footage
Square footage is length × width, measured in feet. For a whole floor, work out each room and add them up.
Measure length and width
Use a tape measure in feet and inches. 6 in is 0.5 ft, so 12 ft 6 in is 12.5 ft.
Multiply them
Length × width gives the square footage of that room.
Add the rooms together
Then subtract anything you don’t need, like a kitchen island, and add 5–15% if you’re buying materials.
Formulas
Square footage formulas for every room shape
Pick the shape in the calculator, or split an odd room into simple shapes and add them.
Rectangle or square
length × width14 × 12 ft = 168 sq ft
L-shaped room
(l₁ × w₁) + (l₂ × w₂)20 × 12 + 10 × 8 = 320 sq ft
Circle
π × (diameter ÷ 2)²10 ft across = 78.54 sq ft
Triangle
½ × base × height24 × 8 ÷ 2 = 96 sq ft
Trapezoid
((a + b) ÷ 2) × depth(8 + 12) ÷ 2 × 5 = 50 sq ft
Measured in feet and inches?
Divide the inches by 12 first: 12 ft 6 in × 10 ft 3 in = 12.5 × 10.25 = 128.13 sq ft. The calculator does this for you in ft + in mode and accepts fractions like 7 1/2.
Quick reference
Room size chart
Common room sizes in square feet and square meters.
Small rooms
Bedrooms, offices, nurseries
- 10 × 10 ft100 sq ft9.29 m²
- 10 × 12 ft120 sq ft11.15 m²
- 12 × 12 ft144 sq ft13.38 m²
Medium rooms
Primary bedrooms, kitchens
- 12 × 14 ft168 sq ft15.61 m²
- 12 × 16 ft192 sq ft17.84 m²
- 14 × 16 ft224 sq ft20.81 m²
Large rooms
Living rooms, open plans, garages
- 15 × 20 ft300 sq ft27.87 m²
- 20 × 20 ft400 sq ft37.16 m²
- 24 × 24 ft576 sq ft53.51 m²
1 sq ft = 144 sq in1 sq yd = 9 sq ft1 m² = 10.764 sq ft1 acre = 43,560 sq ft
Worked example
How to measure an irregular room
Split the floor into rectangles, triangles or circles, find each area, then add them. Subtract anything inside the room you don’t want counted.
1. Sketch and split
Draw the room and divide it into simple shapes. An L-shaped living room becomes a 20 × 12 ft rectangle and a 10 × 8 ft rectangle.
2. Measure each part
Measure wall to wall at floor level. Round to the nearest inch and convert: 7 ft 6 in = 7.5 ft.
3. Add and subtract
240 + 80 = 320 sq ft. Take away a 3 × 6 ft kitchen island and you get 302 sq ft of floor.
Unit conversions
Square feet to square meters and square yards
Carpet is often sold by the square yard, and plans outside the US use square meters. Here are the three conversions you need and common sizes worked out.
- sq ft ÷ 10.764= m²
- sq ft ÷ 9= sq yd
- m² × 10.764= sq ft
Small bedroom10 × 10 ft
100 sq ft
- Square meters
- 9.29 m²
- Square yards
- 11.11 sq yd
Primary bedroomabout 14 × 14 ft
200 sq ft
- Square meters
- 18.58 m²
- Square yards
- 22.22 sq yd
Studio apartmentone open room
500 sq ft
- Square meters
- 46.45 m²
- Square yards
- 55.56 sq yd
Two-bedroom apartmenttypical unit
1,000 sq ft
- Square meters
- 92.90 m²
- Square yards
- 111.11 sq yd
Single-family homeaverage size
2,000 sq ft
- Square meters
- 185.81 m²
- Square yards
- 222.22 sq yd
One acreland area
43,560 sq ft
- Square meters
- 4,046.86 m²
- Square yards
- 4,840 sq yd
Next steps
What to do with your square footage
Buy flooring
Laminate, vinyl plank, hardwood and tile are sold by the box. The flooring calculator adds waste and rounds up to whole boxes.
Price a job or a home
Contractors quote painting, flooring and building per square foot. Check a quote or a listing with the price per square foot calculator.
Measure a whole house
For a listing, appraisal or insurance, living area follows ANSI Z765 rules. Use the house square footage calculator.
FAQ
Square footage questions
Short answers to what people ask most.
How do you calculate square footage?
Measure the length and width in feet and multiply them. A 14 ft by 12 ft room is 168 square feet. For several rooms, calculate each one and add them together.
How do I calculate the square footage of multiple rooms?
Find the square footage of each room separately (length × width), then add the results. In the calculator, use Add room for each space and it keeps a running total.
How many square feet is a 12x12 room?
A 12 by 12 ft room is 144 square feet, which is about 13.38 square meters.
How do I calculate square footage with inches?
Divide the inches by 12 and add them to the feet, so 10 ft 3 in becomes 10.25 ft. Then multiply length by width. If you measured everything in inches, multiply and divide by 144.
How do I measure an L-shaped or irregular room?
Split it into rectangles, find the square footage of each, and add them. Choose L-shape in the calculator, or add each part as a separate room. Use Subtract an area for islands or other spaces you want to leave out.
How much extra flooring should I buy?
Add about 10% for a straight layout, 15% for diagonal layouts or tile, and 20% for herringbone. The waste option in the calculator adds this for you.
How do I convert square feet to square meters?
Multiply square feet by 0.0929. For example, 168 sq ft × 0.0929 = 15.61 m². To go the other way, multiply square meters by 10.764.
Do closets and hallways count in square footage?
Yes. For a home's living area, closets, hallways and stairs inside finished space all count. For flooring, add any closet the new floor will run into.
How many square feet is a 10x10 room?
A 10 ft by 10 ft room is 100 square feet, or 9.29 square meters.
How do I convert square feet to square yards?
Divide square feet by 9. A 360 sq ft room is 40 square yards, which is how carpet is often priced.
How many square feet are in an acre?
One acre is 43,560 square feet, or about 4,047 square meters.