How to Measure Square Footage of Any Space
Rectangles, L-shapes and triangles — plus the waste allowance flooring projects need.
3 min read
Step by step
- Measure each room's length and width in feet and multiply.
- Break L-shapes into two rectangles and add them.
- Triangles are (base × height) ÷ 2.
- Add 5–10% waste for flooring and tile cuts.
Key takeaway: Measure room by room, then add a waste allowance.
Rectangles first
Square footage is length × width for each rectangular space, summed. Measure wall to wall in feet and inches, convert inches to decimals (6 in = 0.5 ft), and round up slightly rather than down.
A 12 ft 6 in × 10 ft room is 12.5 × 10 = 125 sq ft. Measure every room separately — closets and hallways count in real-estate and flooring contexts.
Odd shapes
Break L-shaped rooms into two rectangles and add them. Triangles are (base × height) ÷ 2; circles are π × radius². For flooring, add 5–10% waste for cuts — more for diagonal layouts.
Note that listings and appraisals use specific standards (like ANSI in the US) that exclude garages and below-grade spaces; your project measurement may legitimately differ.
Why the number matters
Flooring, tile, carpet, paint, sod and HVAC sizing are all priced or specified per square foot, so an accurate area is the foundation of an accurate budget.
Converting to square meters (divide by 10.764) is essential when buying materials sold in metric units.
Do it automatically
Total area in square feet and square meters for one or more rooms.
Open the Square Footage Calculator