Room Square Footage Calculator
Measure any room in your house. Enter the length and width in feet or inches — we'll show you the square footage, plus conversions to square meters, yards, and acres.
Last updated:Tip: If you only have the diameter, divide by 2 to get the radius.
L-shape = two rectangles sharing a corner.
Add one row per rectangle and we'll sum them.
How to Measure a Room for Square Footage
For a rectangular room, the measurement is straightforward:
- Measure the length — the longest wall, baseboard to baseboard, in feet (use the inch unit if needed).
- Measure the width — the wall perpendicular to the length.
- Multiply length × width. That's your room's square footage.
If the room is L-shaped or has alcoves, switch to the L-Shape or Irregular tab above and enter each rectangle separately.
Common Room Sizes in North America
| Room Type | Typical Size | Square Footage |
|---|---|---|
| Small bedroom | 10 × 10 ft | 100 sq ft |
| Standard bedroom | 10 × 12 ft | 120 sq ft |
| Master bedroom | 12 × 15 ft | 180 sq ft |
| Living room | 15 × 20 ft | 300 sq ft |
| Kitchen | 10 × 14 ft | 140 sq ft |
| Full bathroom | 5 × 8 ft | 40 sq ft |
| Dining room | 12 × 12 ft | 144 sq ft |
| Two-car garage | 20 × 20 ft | 400 sq ft |
What Counts as Livable Square Footage?
When measuring the square footage of a home for a listing or appraisal, only heated, finished, and permanently enclosed spaces count. Typically excluded are garages, unfinished basements, screened porches, and open stairwells. This follows the ANSI Z765 standard used across most of North America.
For real estate listings, the square footage is usually measured from the outside of exterior walls. For interior design or flooring, measure from wall to wall on the inside.
Frequently Asked Questions
How do I calculate the square footage of a room with closets?
Measure the main room first. If the closet is enclosed with a door, most listings include its square footage in the room total. Add the closet's length × width to the room's area.
What if my room isn't rectangular?
Use the L-Shape tab for simple L rooms, or Irregular for rooms with multiple alcoves. Break the floor plan into rectangles and enter each one.
How many square feet is a 12x12 room?
A 12 × 12 room is 144 square feet. See 12x12 room details for unit conversions and typical uses.
Do I include the closet when calculating a bedroom?
Yes, if the closet is enclosed and part of the room's heated space, it counts. Walk-in closets are always included.
How accurate does my measurement need to be?
For flooring, round to the nearest inch. For real estate, appraisers measure to the nearest half-inch. A 1-inch error on a 12-foot wall changes the area by less than 1%.