The basic formula: length × width
- Measure the length of the room wall to wall, in feet.
- Measure the width.
- Multiply. A 14 ft × 12 ft room = 168 sq ft.
Use a 25-foot tape measure or a laser measure, measure at floor level, and round to the nearest inch.
How to calculate square feet with feet and inches
Convert the inches into a decimal of a foot by dividing by 12, then multiply.
| Inches | Feet (decimal) |
|---|---|
| 1 in | 0.08 |
| 2 in | 0.17 |
| 3 in | 0.25 |
| 4 in | 0.33 |
| 6 in | 0.5 |
| 8 in | 0.67 |
| 9 in | 0.75 |
| 10 in | 0.83 |
L-shaped rooms and odd shapes
Split the space into rectangles, find each area and add them. For an L-shaped living room, measure the main part (say 18 × 12 = 216 sq ft) and the nook (8 × 6 = 48 sq ft): total 264 sq ft. For a bay window or angled corner use a triangle (base × height ÷ 2). For a round area use 3.1416 × radius × radius.
How to find the square footage of a house
Listings in the US usually report finished, heated living area. The common standard (ANSI Z765) measures from the outside of exterior walls and leaves out garages, unfinished basements, porches and areas with very low ceilings. Basements are often listed separately even when finished. To estimate yourself, measure the outside of the house, multiply, and subtract the garage and other unfinished areas. For two-story homes, add each floor.
Flooring, tile and paint
| Project | How to work it out |
|---|---|
| Flooring / tile | Room sq ft × 1.10 (10% waste), or × 1.15 for diagonal and patterns. Divide by sq ft per box, round up. |
| Carpet | Usually sold by the square yard: sq ft ÷ 9. |
| Wall paint | Wall area = perimeter × ceiling height, minus about 20 sq ft per door and 15 per window. One gallon covers about 350–400 sq ft per coat. |
| Baseboard | Perimeter in linear feet minus door openings. |
Square footage conversions
| From | To | Multiply by |
|---|---|---|
| Square feet | Square meters | 0.0929 |
| Square meters | Square feet | 10.764 |
| Square feet | Square yards | ÷ 9 |
| Acres | Square feet | 43,560 |
Questions
How many square feet is a 10x12 room?
120 square feet.
How do I calculate square feet for a room with a closet?
Measure the closet as its own rectangle and add it to the room. For flooring, include it; for listing square footage it already counts as part of the living area.
How much is 500 square feet?
Roughly a studio apartment or a 20 × 25 ft space. It’s about 46.5 square meters.
How do I calculate square footage for a circle?
Measure the diameter (across the middle), divide by 2 to get the radius, then multiply 3.1416 × radius × radius. A 12-ft round patio is 3.1416 × 6 × 6 = 113 sq ft.