How it works
A rectangular room's floor area is simply length times width. Most real rooms aren't perfect rectangles, but almost any floor plan can be split into two or more rectangles — an L-shaped room is just a big rectangle with a smaller one attached, and their areas add together to give the true total.
area = length × width
total area = rectangle 1 + rectangle 2 (if added)
Worked example
A 12 ft × 10 ft room with a 6 ft × 4 ft alcove.
- Main rectangle: 12 × 10 = 120 sq ft.
- Alcove: 6 × 4 = 24 sq ft.
- Total: 120 + 24 = 144 sq ft.
The room's total floor area is 144 sq ft.
Common questions
What if my room has more than two rectangles?
Calculate any extra rectangles separately (or with a second visit to this calculator) and add their areas to the total shown here — the same split-and-add approach extends to any number of pieces.
Does this account for closets, alcoves or bump-outs?
Only if you model them as a rectangle using the second-rectangle option. A small closet that adds floor area should be added; one that's just built into a wall recess without adding usable floor space shouldn't be.
Why might my measured area not match a listing's square footage?
Listed square footage often follows local measurement standards that include or exclude things like closets, stairwells or wall thickness differently. This calculator gives you the raw floor area of whatever rectangles you enter.