How to Measure Square Footage of a Room: Step by Step

What to bring

A tape measure or suitable laser measure, a pencil and a rough floor sketch are enough for a planning estimate. A second person can help keep a long tape straight. Record each dimension immediately.

1. Draw the outline. Include door recesses, closets, bay windows and fixed fixtures. Label the room and floor.
2. Measure length and width. Keep the tape level and straight. For flooring estimates, measure the surface you expect to cover.
3. Split irregular rooms. Divide an L-shape into two rectangles that meet without overlapping. For angled walls, measure a perpendicular height for the triangular portion.
4. Add closets separately. Measure beyond the doorway. Name the closet in your room list so its area is counted once.
5. Check fixtures. Only subtract an island or cabinet if the flooring plan excludes the area beneath it. Follow installation instructions.
6. Handle stairs separately. For material estimates, measure tread and riser surfaces required by your product; do not add those surfaces to ordinary flat floor area. Landings are separate flat areas. Living-area reporting may treat stairs differently.
7. Repeat and review. Recheck long dimensions and compare your sketch with the room. Add a cutting allowance suited to the product and pattern.

Example: bedroom and closet

A 12 × 10 ft bedroom and a 3 × 4 ft closet total 132 sq ft. At 10% extra, that is 145.2 sq ft; with 20 sq ft per box, buy 8 boxes if those assumptions suit the installation.

Enter the two spaces in the room square footage calculator. For selling or appraising a house, use the applicable measurement standard with a qualified professional; a flooring sketch is not a certified living-area report.

Formulas and exact conversion constants: methodology and sources.