How to Calculate Square Footage of Any Room
Knowing the accurate square footage of a room is essential for flooring, painting, heating and cooling estimates, and real estate comparisons. The math is simple, but measuring accurately takes care.
Simple Rectangular Room
Area = Length × Width
Example: 14 ft × 12 ft = 168 sq ft
L-Shaped Room
Divide into two rectangles:
- Rectangle 1: 14 × 10 = 140 sq ft
- Rectangle 2: 8 × 6 = 48 sq ft
- Total: 188 sq ft
Measuring Tips
- Measure wall to wall at the floor level—not at countertop height
- Convert inches to decimals: 9 ft 6 in = 9.5 ft
- Don't exclude closets unless calculating for flooring that won't be installed there
- Measure twice before ordering materials
Including Odd Shapes
Triangle alcove: Area = ½ × base × height For a 6 × 4 ft triangular nook: ½ × 6 × 4 = 12 sq ft
Bay window: Measure each wall segment separately and add to main room area.
Total House Square Footage
For total home square footage:
- Include all finished, heated/cooled living areas
- Typically exclude: garage, unfinished basement, covered porches (varies by region)
- Standard is to measure from exterior wall to exterior wall (including wall thickness)
Quick Reference
| Room Size | Square Footage |
|---|---|
| 10 × 10 | 100 sq ft |
| 12 × 12 | 144 sq ft |
| 15 × 20 | 300 sq ft |
| 20 × 30 | 600 sq ft |
Use our square footage calculator to add up multiple rooms or irregular spaces.