Square Footage Calculator
Calculate square footage from room dimensions, feet-and-inches measurements, triangles, or circles.
This page keeps square feet as the main result and includes quick conversions to square yards, acres, square meters, and square inches.
Results
This is a quick square footage calculator for simple areas. Use trade-specific calculators for roof pitch, flooring boxes, tile waste, or material quantities.
How to use this calculator
- 01Choose rectangle / room, triangle, or circle.
- 02Enter the dimensions in feet and inches.
- 03Read the square footage as the primary result.
- 04Use the square yards, acres, and square meters rows when you need a quick conversion.
For roof surface area with pitch, use the Roof Square Footage Calculator. For material counts, use the Flooring Calculator or Tile Calculator. For metric-first area inputs, use the Square Meter Calculator. For area plus depth volume, use the Cubic Feet Calculator. For square feet to linear feet by material width, use the Linear Feet Calculator. For square-yard conversions, use the Square Yard Calculator.
Understanding the math
Square footage is area measured in square feet. Convert inches to feet before multiplying, or divide square inches by 144 when you already have a square-inch area.
rectangle_area = length x width triangle_area = base x height / 2 circle_area = pi x (diameter / 2)^2 square_yards = square_feet / 9 acres = square_feet / 43560 square_meters = square_feet x 0.09290304
Square footage conversion table
Use these common conversions as a quick check when you need square yards, acres, or square meters from a square-foot area.
| Square feet | Square yards | Acres | Square meters |
|---|---|---|---|
| 1 sq ft | 0.111 sq yd | 0.00002 acres | 0.093 m² |
| 10 sq ft | 1.11 sq yd | 0.00023 acres | 0.93 m² |
| 100 sq ft | 11.11 sq yd | 0.0023 acres | 9.29 m² |
| 1,000 sq ft | 111.11 sq yd | 0.023 acres | 92.9 m² |
| 43,560 sq ft | 4,840 sq yd | 1 acres | 4,047 m² |
Frequently asked questions
How to calculate square footage?
For a rectangle or room, multiply length by width. This calculator also handles triangles with base x height / 2 and circles with pi x radius squared.
How to calculate square footage of a room?
Measure the room length and width in feet, convert any extra inches to feet, then multiply length by width. For example, 10 ft 6 in is 10.5 ft.
How to calculate square footage from inches?
Convert inches to feet first by dividing by 12. If you already have square inches, divide by 144 to get square feet.
How to calculate square footage of a triangle?
Multiply the triangle base by its height, then divide by 2. Base and height must meet at a right angle for the area formula.
How to calculate square footage of a circle?
Use pi x radius squared. If you measured diameter, divide it by 2 first to get the radius.
Related calculators
Linear Feet Calculator
Convert square feet to linear feet using material width, or calculate total run length.
Square Yard Calculator
Convert square feet to square yards or calculate square yards from simple shapes.
Cubic Feet Calculator
Calculate cubic feet from area plus depth, room dimensions, or cylinder measurements.
Square Meter Calculator
Calculate square meters from metric room, triangle, or circle dimensions.
Roof Square Footage Calculator
Calculate roof surface area with pitch multiplier, waste, and roofing squares.
Flooring Calculator
Estimate flooring boxes, waste, underlayment, and material cost from floor area.
Tile Calculator
Estimate tile count, grout, thinset, cuts, and waste for floor or wall layouts.