Square Footage Calculator
Multiply length × width to find square feet for any rectangular area.
Multiply length × width to find square feet for any rectangular area.
Square footage is the area of a flat surface measured in square feet, where one square foot is a square 1 foot long on each side. For a rectangle, the square footage is length × width, both in feet: a room 12 feet by 15 feet is 180 square feet. It is the basic number behind most home projects, from flooring and paint to concrete slabs, sod, and listing a home for sale.
Getting an accurate answer depends mostly on how you measure. Measure wall to wall at floor level, round up to the nearest inch, and convert inches to feet by dividing by 12, so 10 feet 6 inches becomes 10.5 feet. Rooms that are not simple rectangles, such as L-shaped rooms or open floor plans, should be split into rectangles, calculated one at a time, and added together. The purpose also matters: flooring and tile orders usually add 10–15% for cuts and waste, paint coverage uses wall area rather than floor area, carpet is often priced by the square yard (divide square feet by 9), and concrete needs a depth to turn area into volume. Real estate square footage follows its own measuring standards, so it may not match a quick room-by-room total.
To use this square footage calculator, enter the length and the width in feet. Decimals work, so a measurement of 12 feet 3 inches can be entered as 12.25. The tool multiplies the two numbers and shows the result in square feet. For an irregular space, run the calculator once for each rectangular section and add the results. Use the total to estimate materials, then add any waste allowance your project needs.
Length × Width = Square feet. Enter both measurements in feet. Decimals like 12.5 are fine.
| Length | Width | Square feet |
|---|---|---|
| 10 ft | 10 ft | 100 sq ft |
| 12 ft | 10 ft | 120 sq ft |
| 15 ft | 20 ft | 300 sq ft |
Feet. If you have inches, divide by 12 first or use the feet-to-inches converter.
Yes — for volume, also use the Concrete Bag Calculator.
Yes — 12.5 ft by 8.75 ft works fine.
Results are estimates for planning purposes. Verify with product labels and local requirements before purchasing materials.
Square footage is the area of any flat surface, measured in square feet. To calculate it, multiply the length by the width — both measured in feet. The formula is: Square feet = Length (ft) × Width (ft)
If your measurements are in inches, divide each by 12 before multiplying. If you have a room with an L-shape or irregular footprint, break it into rectangles, calculate each section separately, and add the results together.
| Space | Typical dimensions | Square footage | Common use |
|---|---|---|---|
| Small bedroom | 10×10 ft | 100 sq ft | Child's room, office |
| Standard bedroom | 12×12 ft | 144 sq ft | Most common bedroom size |
| Large bedroom | 14×16 ft | 224 sq ft | Master bedroom |
| Small bathroom | 5×8 ft | 40 sq ft | Half bath / powder room |
| Standard bathroom | 8×10 ft | 80 sq ft | Full bath |
| Kitchen | 10×12 ft | 120 sq ft | Average US kitchen |
| Living room | 15×20 ft | 300 sq ft | Standard living room |
| 1-car garage | 12×20 ft | 240 sq ft | Single vehicle |
| 2-car garage | 20×22 ft | 440 sq ft | Two vehicles |
| Standard patio | 10×14 ft | 140 sq ft | Outdoor entertaining |
| Driveway (1 car) | 10×20 ft | 200 sq ft | Single car width |
| Driveway (2 car) | 20×20 ft | 400 sq ft | Double car width |
Measure your room square footage, then add 10% waste for straight-lay flooring or 15% for diagonal or herringbone patterns. Always buy from the same dye lot. Carpet is sold by the square yard (divide sq ft by 9).
| Room | Area | Order (10% waste) | Order (15% waste) |
|---|---|---|---|
| 12×12 bedroom | 144 sq ft | 158 sq ft | 166 sq ft |
| 14×16 bedroom | 224 sq ft | 246 sq ft | 258 sq ft |
| 10×12 kitchen | 120 sq ft | 132 sq ft | 138 sq ft |
| 15×20 living room | 300 sq ft | 330 sq ft | 345 sq ft |
| 8×10 bathroom | 80 sq ft | 88 sq ft | 92 sq ft |
For wall paint, calculate perimeter × ceiling height, then subtract 20 sq ft per door and 15 sq ft per window. One gallon covers 350–400 sq ft. Most rooms need two coats.
For slabs, patios, and driveways, square footage is the starting point for calculating volume. Multiply square footage by depth in feet to get cubic feet, then divide by 27 for cubic yards.
Sod is sold by the square foot or square yard. Measure your lawn area, subtract beds and walkways, and add 5–10% waste for cuts around edges.
| To convert | Multiply by | Example |
|---|---|---|
| Square feet → Square yards | ÷ 9 | 270 sq ft = 30 sq yd |
| Square feet → Square meters | × 0.0929 | 100 sq ft = 9.29 sq m |
| Square feet → Acres | ÷ 43,560 | 87,120 sq ft = 2 acres |
| Square yards → Square feet | × 9 | 30 sq yd = 270 sq ft |
| Square meters → Square feet | × 10.764 | 100 sq m = 1,076.4 sq ft |
| Acres → Square feet | × 43,560 | 1 acre = 43,560 sq ft |
Multiply the length by the width of the room in feet. A room 14 feet long and 12 feet wide is 168 square feet. For rooms with irregular shapes, break them into rectangles, calculate each section, and add the totals.
A 12×12 foot room is exactly 144 square feet. This is a common bedroom size and a useful mental reference — it takes about 144 tiles (12×12 inch), roughly 3 gallons of paint for walls, or about 160 square feet of flooring with waste.
One acre equals 43,560 square feet. A standard American football field (end zones included) is approximately 57,600 square feet, or about 1.32 acres.
Divide the L-shape into two rectangles. Measure each rectangle separately, calculate each area (length × width), and add the two totals. For example: 15×12 ft (180 sq ft) + 8×10 ft (80 sq ft) = 260 sq ft total.
Order 10% extra for straight-lay patterns. Order 15% extra for diagonal tile or herringbone patterns due to increased cuts at edges. Always buy from the same dye lot — color can vary between production runs.
Divide square feet by 9. There are 9 square feet in one square yard. For example, 270 square feet = 30 square yards. Carpet and some other flooring is sold by the square yard, so this conversion matters for estimates.
Measure your wall perimeter (add all four wall lengths) and multiply by ceiling height. Then subtract 20 square feet per door and 15 square feet per window. Divide by 350 (standard gallon coverage) for gallons needed per coat.
Square footage = Length (in feet) × Width (in feet). Both measurements must be in feet. If you have inches, divide by 12 first. If you have meters, multiply by 10.764 to convert to square feet.
For a circle, multiply π (about 3.1416) by the radius squared: a 10-foot-diameter patio is 3.1416 × 5 × 5 ≈ 78.5 sq ft. For a triangle, multiply base × height and divide by 2: a 10 by 6 foot triangle is 30 sq ft. This calculator handles rectangles, so use these formulas for curved or angled areas.
Multiply square meters by 10.7639. For example, 20 square meters × 10.7639 ≈ 215.3 square feet; to go the other way, divide square feet by 10.7639.