Room Sqft Calculator
Measure one room, or use the Multiple rooms tab to add them all up and get a total for the whole house.
To calculate the square footage of a room, multiply its length by its width in feet. A room 14 ft by 12 ft is 14 × 12 = 168 square feet. For an L-shaped room, split it into two rectangles, work out each one, and add them together.
Formula: Length × Width
Formula: Overall area − notch
How to measure a room properly
Accuracy here matters more than people expect — a 3-inch error on each wall of an average room shifts the total by several square feet, which is a whole box of flooring.
- Measure at floor level, wall to wall. Skirting boards and baseboards taper, so measuring higher up gives a slightly short reading.
- Take the longest and widest points. Rooms are rarely perfectly square. If two opposite walls differ, use the larger figure for materials.
- Record feet and inches, then convert. 12 ft 7 in becomes 12.583 ft. Or select Feet + inches above.
- Handle alcoves separately. Bay windows, closets and chimney breasts are their own small rectangles — add or subtract them.
A total on its own is hard to picture. Seeing what 500 square feet looks like as room dimensions is often the sanity check that catches a measuring error.
Totalling a whole house
Switch to the Multiple rooms tab and add a row per room. The running total updates as you go.
For a house measurement that will be quoted to anyone else, the convention is to include hallways, landings and closets in the finished living area, and exclude garages, unfinished basements and anything with a ceiling below 7 feet. Our guide to house square footage covers the rules in full.
Turning room size into a materials order
Once you have the area, add a waste allowance before ordering — the field is built into the calculator above.
- 10% for straightforward rectangular rooms with a straight-lay pattern
- 15% for diagonal or herringbone layouts, and rooms with many corners
- 20% for large-format tile, where a bad cut wastes a lot of material
A 168 sq ft room with a 10% allowance means ordering 185 sq ft.
Common room sizes in square feet
| Room | Typical size | Square feet |
|---|---|---|
| Small bedroom | 10 × 10 ft | 100 sq ft |
| Standard bedroom | 12 × 12 ft | 144 sq ft |
| Master bedroom | 14 × 16 ft | 224 sq ft |
| Bathroom | 8 × 5 ft | 40 sq ft |
| Kitchen | 12 × 14 ft | 168 sq ft |
| Living room | 16 × 20 ft | 320 sq ft |
| Half bath | 5 × 4 ft | 20 sq ft |
| One-car garage | 12 × 22 ft | 264 sq ft |
| Two-car garage | 20 × 20 ft | 400 sq ft |
| Three-car garage | 32 × 22 ft | 704 sq ft |
Frequently asked questions
How do I calculate the sqft of a room?
Measure the length and width in feet and multiply them. A room 14 feet by 12 feet is 168 square feet. For rooms that are not rectangular, split them into rectangles and add the parts.
How many square feet is a 12x12 room?
A 12 by 12 foot room is 144 square feet.
How do I measure an L-shaped room?
Draw a line across the inside corner to divide it into two rectangles. Measure and calculate each rectangle separately, then add them. Alternatively measure the full bounding rectangle and subtract the missing corner.
Do closets count in a room measurement?
For flooring, yes — you will be laying material in them. For a listed house size, built-in closets are normally included in the finished living area.
Should I measure at floor level or waist height?
At floor level, wall to wall. Baseboards and skirting taper outward at the bottom, so measuring higher up gives a slightly smaller reading than the actual floor area you need to cover.
How many square feet is a 10x10 room?
A 10 by 10 foot room is 100 square feet. Multiply the two sides — the same rule applies to any rectangular room.
How many square feet is a 2 car garage?
A standard two-car garage is 20 × 20 ft, which is 400 square feet. Builders commonly go to 20 × 22 ft (440 sq ft) or 24 × 24 ft (576 sq ft) where the plot allows. Note that a garage does not count toward a home’s finished square footage.
How many square feet is a 1 car garage?
A single-car garage is typically 12 × 22 ft, or 264 square feet. The practical minimum is about 10 × 20 ft (200 sq ft), which fits the car but leaves little room to open the doors.
How many square feet is a 3 car garage?
A three-car garage is usually 32 × 22 ft, around 704 square feet. Wider layouts run to 36 × 24 ft, about 864 square feet.
What is the recommended minimum square footage for a bathroom?
A half bath (toilet and basin) needs about 18–20 square feet, with 15 sq ft the usual code-driven minimum. A full bathroom with a tub or shower needs 35–40 square feet. Master bathrooms typically run 100–150 square feet. Local building codes set clearance distances rather than a floor area, so check yours before finalising a layout.
What is the average square footage of a bedroom?
A standard US bedroom is around 132 square feet (11 × 12 ft). Small or children’s bedrooms run 100 sq ft, and master bedrooms average 224 sq ft (14 × 16 ft). Most codes require a habitable bedroom to be at least 70 square feet with no dimension under 7 feet.