Square Footage Calculator
Calculate the square footage of any room, yard, or surface with our free calculator. Whether you're measuring for flooring, paint, landscaping, or construction materials, knowing your exact square footage is essential for accurate estimates and budgeting. Simply enter your dimensions and instantly get results in square feet, square yards, and square meters. Our calculator handles rectangular, circular, and triangular areas, covering virtually any space you need to measure.
- Free forever
- Formula-sourced
- Updated 2026-02-04
- No sign-up
For rectangles and squares
For rectangles; same as length for squares
For circles only
For triangles only
For triangles only
Visual Preview
Fill in the form to see your estimate.
How It's Calculated
Rectangle/Square: Area = Length × Width Circle: Area = π × (Diameter ÷ 2)² Triangle: Area = (Base × Height) ÷ 2 The calculator converts results to multiple units: • Square Yards = Square Feet ÷ 9 • Square Meters = Square Feet × 0.0929 • Acres = Square Feet ÷ 43,560
Worked Examples
An 18-foot by 14-foot living room has an area of 252 square feet (18 × 14 = 252). This equals 28 square yards or about 23.4 square meters.
A circular patio with a 12-foot diameter has an area of approximately 113 square feet. The formula uses π × 6² (where 6 is the radius).
A triangular garden bed with a 10-foot base and 8-foot height has an area of 40 square feet ((10 × 8) ÷ 2 = 40).
Assumptions & Waste Factor
- All measurements are in feet
- Shapes are regular (true rectangles, perfect circles, right triangles)
- For irregular shapes, break into smaller regular shapes and add areas together
- Conversion: 1 square yard = 9 square feet
- Conversion: 1 square meter = 10.764 square feet
Square footage calculations typically don't include waste. Add waste factor when calculating materials (typically 5-15% depending on the project type).
Frequently Asked Questions
How do I calculate square footage for an L-shaped room?
Divide the L-shape into two rectangles. Calculate the area of each rectangle separately (length × width), then add them together. For example, if one section is 10×12 and another is 8×6, total area is 120 + 48 = 168 square feet.
What is the difference between square feet and linear feet?
Square feet measures area (two dimensions, length times width), while linear feet measures length only (one dimension). A 10×10 room is 100 square feet of floor area but 40 linear feet of wall perimeter.
How do I convert square feet to square yards?
Divide the square footage by 9. For example, 180 square feet equals 20 square yards (180 ÷ 9 = 20). This is useful when buying carpet, which is often priced per square yard.
How many square feet is a 12x12 room?
A 12×12 room is exactly 144 square feet (12 × 12 = 144). This is the same as 16 square yards or about 13.4 square meters.
How do I measure an irregularly shaped area?
Break the irregular shape into basic shapes (rectangles, triangles, circles). Measure and calculate each section separately, then add all the areas together for the total square footage.
Should I round up or down when calculating square footage?
For material purchases, always round up to ensure you have enough. For cost estimates, use the exact calculation. Most building materials include extra for cutting waste anyway.
How accurate does my measurement need to be?
For most home projects, measuring to the nearest inch is sufficient. Professional contractors often measure to the nearest quarter inch. Always round up dimensions when ordering materials.
How do I measure for flooring when there are closets?
Include closets in your square footage calculation since they need flooring too. Measure the main room and each closet separately, then add all areas together.
Related Calculators5 related
Related Guide
Disclaimer: This calculator provides estimates for planning purposes only. Actual material requirements may vary based on site conditions, installation methods, and other factors. Always consult with a qualified professional before making purchasing decisions.