Square Footage Calculator
Calculate area in square feet, square meters and square yards for rooms, floors, walls, land and more.
Last updated: September 2026 · Area formulas and unit conversions reviewed (not a property survey or legal boundary measurement)
Best for rectangles, circles, and triangles. Split L-shapes into sections and add the areas. Results are geometric sq ft, sq m, and sq yd from the dimensions you enter — not a survey, appraisal, or material order with waste. Use flooring, tile, or paint calculators next when ordering products.
Quick Answer: Area Formulas
Rectangle: length × width
Circle: π × (diameter ÷ 2)²
Triangle: (base × height) ÷ 2
Conversions: 1 m² ≈ 10.764 ft² · 1 yd² = 9 ft²
Use the same unit for every side. For L-shapes, split into rectangles and add the areas.
How to Use This Square Footage Calculator
- Select the shape: Rectangle, Circle or Triangle
- Enter the dimensions in your preferred unit (feet, meters, inches or yards)
- Optionally add price per square foot for a cost estimate
- Click Calculate Area to see results in sq ft, sq m and sq yd
Room Area Examples (Sq Ft, Sq M, Sq Yd)
Quick reference for rectangular rooms. Re-calculate with the tabs above for circles, triangles, or other units.
| Room Size | Square Feet | Square Meters | Square Yards |
|---|---|---|---|
| 8 × 10 ft | 80 ft² | 7.4 m² | 8.9 yd² |
| 10 × 12 ft | 120 ft² | 11.1 m² | 13.3 yd² |
| 12 × 15 ft | 180 ft² | 16.7 m² | 20.0 yd² |
| 15 × 20 ft | 300 ft² | 27.9 m² | 33.3 yd² |
| 20 × 20 ft | 400 ft² | 37.2 m² | 44.4 yd² |
For flooring or carpet, add 5–10% waste on top of these numbers — or use the flooring and tile calculators.
Worked example (12 × 15 ft room)
- Area = 12 × 15 = 180 ft²
- ÷ 9 = 20 yd²
- ÷ 10.764 ≈ 16.7 m²
Circle example (10 ft diameter)
Radius = 5 ft → Area = π × 5² ≈ 78.54 ft² ≈ 7.30 m² ≈ 8.73 yd². Use the Circle tab above.
Triangle example (base 12 ft, height 8 ft)
Area = (12 × 8) ÷ 2 = 48 ft² ≈ 4.46 m² ≈ 5.33 yd². Use the Triangle tab above.
L-shaped room example
Split into two rectangles and add:
- Main section 10 × 12 ft = 120 ft²
- Leg section 6 × 8 ft = 48 ft²
- Total = 120 + 48 = 168 ft² ≈ 15.6 m² ≈ 18.7 yd²
Run the Rectangle tab twice (or once per section) and add the results. Do not try to enter an L as a single length × width.
Common Uses
| Use Case | What to Measure |
|---|---|
| Flooring / Carpet | Room length × width |
| Paint / Wallpaper | Wall length × height (minus openings) |
| Land / Lawn | Property dimensions |
| Tile / Hardwood | Floor area + waste |
| Concrete Slab | Length × width |
After you have area, order materials with waste built in:
- Flooring calculator — planks, boxes, waste %
- Tile calculator — tiles, grout gap, boxes
- Paint calculator — wall/ceiling gallons (not floor area alone)
- Concrete calculator — area × depth → yards and bags
Price per sq ft: Optional field above is a rough materials ballpark only — not a contractor bid, tax assessment, or appraisal.
Formulas Used
Rectangle: Area = Length × Width
Circle: Area = π × (Diameter ÷ 2)²
Triangle: Area = (Base × Height) ÷ 2
Conversions: 1 m² ≈ 10.764 ft² · 1 yd² = 9 ft² · 1 acre = 43,560 ft²
Area conversion reference
| From | To | Multiply by |
|---|---|---|
| 1 ft² | m² | ÷ 10.764 ≈ × 0.0929 |
| 1 ft² | yd² | ÷ 9 |
| 1 m² | ft² | × 10.764 |
| 1 yd² | ft² | × 9 |
| 1 acre | ft² | × 43,560 |
| 1 acre | m² | ≈ × 4,047 |
Measuring Rooms, Walls & Irregular Shapes
Square footage is one of the most common measurements in home improvement, real estate and construction. Accurate area calculations help you order the right amount of flooring, paint, tile or landscaping materials.
Rectangular rooms & ceilings
Most rooms are rectangular. Measure length and width in feet, then multiply. Example: a 12 ft × 10 ft room = 120 square feet. For a simple rectangular room, ceiling area is usually the same as floor area (length × width).
Irregular shapes & L-plans
Break the space into rectangles, circles, or triangles. Calculate each part separately and add the results. See the L-shaped worked example above (10×12 + 6×8 = 168 ft²).
Walls for paint
Measure the length of each wall and multiply by ceiling height. Subtract doors and windows for a more accurate paint estimate, then use the paint calculator for gallons. Wall area is not the same as floor square footage.
Outdoor / lot area
Measure lawn or pad sections the same way — rectangles and triangles work for many lots. Divide large totals by 43,560 for a rough acre figure. This is still a geometric estimate, not a survey or tax-map measurement.
Tips for Accurate Measurements
- Use the same unit for all measurements before calculating.
- Measure twice — small errors multiply on large areas.
- Add waste — 5–10% extra is common for flooring, tile and carpet.
- Account for openings when calculating wall area for paint or wallpaper.
- Net vs gross: Closets and nooks count if you are flooring them; exclude areas you will not cover.
- Round up when ordering materials so you do not run short.
Important: This calculator returns geometric area from the dimensions you enter. It is not a property survey, appraisal, or legal boundary measurement. For materials, add waste separately (or use the flooring, tile, or paint calculators) and confirm openings, stairs, and built-ins on site.