How to Measure the Square Footage of a Room
Part of Area & Volume
Quick answer
Measure the room's length and width in feet, then multiply them: a 12 ft × 14 ft room is 168 square feet. For an L-shaped or alcoved room, split it into rectangles, find each area, and add them together.
A room's square footage is just its floor area in feet. For a plain rectangular room it's one measurement times another; the only real work is handling closets, bump-outs and odd shapes.
Step by step
- Measure the longest wall (the length) in feet, then the wall next to it (the width).
- Multiply length × width — that's the square footage of a rectangular room.
- Measured in inches? Divide each number by 12 to get feet first, or multiply inches × inches and divide by 144.
- Add closets, alcoves and bump-outs as separate rectangles and total them.
Common room sizes
| Room | Dimensions | Square footage |
|---|---|---|
| Small bedroom | 10 × 10 ft | 100 ft² |
| Standard bedroom | 12 × 12 ft | 144 ft² |
| Master bedroom | 14 × 16 ft | 224 ft² |
| Living room | 16 × 20 ft | 320 ft² |
| 1-car garage | 12 × 20 ft | 240 ft² |
Odd-shaped rooms
- L-shape: divide it into two rectangles, find each area, and add them.
- Alcove or bay: measure it as its own small rectangle and add it on.
- Angled corner: treat it as a triangle — (base × height) ÷ 2 — and add it.
- Round column or pillar you're flooring around: subtract its area (π × radius²).
Whole-house square footage
To get a home's total, measure each room and hallway separately and add them up. For flooring or paint, total only the rooms you're working on — and round up a little for waste. The square footage calculator adds multiple rectangles for you and keeps the running total.
FAQs
How do I measure square footage of a room with a closet?
Measure the main room as one rectangle (length × width), measure the closet as its own rectangle, then add the two areas together for the total.
Do you include closets in a room's square footage?
For flooring and paint estimates, yes — you'll cover the closet floor too, so include it. For listing a home's living area, built-in closets are typically counted as part of the room.
How many square feet is a 12x12 room?
144 square feet. Multiply 12 ft × 12 ft = 144 ft².