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 Γ— Width

Example: 14 ft Γ— 12 ft = 168 sq ft

L-Shaped Room

Divide into two rectangles:

  • Rectangle 1: 14 Γ— 10 = 140 sq ft
  • Rectangle 2: 8 Γ— 6 = 48 sq ft
  • Total: 188 sq ft

Measuring Tips

  1. Measure wall to wall at the floor levelβ€”not at countertop height
  2. Convert inches to decimals: 9 ft 6 in = 9.5 ft
  3. Don't exclude closets unless calculating for flooring that won't be installed there
  4. Measure twice before ordering materials

Including Odd Shapes

Triangle alcove: Area = Β½ Γ— base Γ— height For a 6 Γ— 4 ft triangular nook: Β½ Γ— 6 Γ— 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 SizeSquare Footage
10 Γ— 10100 sq ft
12 Γ— 12144 sq ft
15 Γ— 20300 sq ft
20 Γ— 30600 sq ft

Use our square footage calculator to add up multiple rooms or irregular spaces.