Square Footage Calculator
Add every room in your project, switch between feet and metres, and get a running total with an optional waste factor for flooring, tile, or paint. Results update as you type, no submit button needed.
| Room name | Length | Width | L-shape | Area | Remove |
|---|
- Total area
- 0 ft²
- With waste factor
- 0 ft²
- Total in the other unit
- 0 m²
- Rooms counted
- 0
How to measure a room for square footage
To find the square footage of a room, measure the length of one wall and the width of the adjacent wall, both in feet. Use a tape measure or a laser measure and run it along the floor from baseboard to baseboard for the most accurate reading. Round to the nearest inch, then convert to a decimal (6 inches becomes 0.5 feet). Multiply length by width to get the area in square feet. For a rectangular room this single calculation is all you need.
Most rooms are not perfect rectangles. Bay windows, closets, alcoves, and open-plan layouts add extra sections. The simplest way to handle this is to break the room into rectangles: measure each rectangular section separately, calculate its area, then add the sections together. If a fixed feature like a fireplace or a stairwell eats into the floor space, measure that section too and subtract it from the total.
Always measure at floor level, not at the widest point of the walls, since baseboards, closet doors, and door swings can make upper measurements misleading. If you are ordering flooring or tile, add a waste factor on top of the raw area to cover cuts, offcuts, and mistakes. This calculator does the arithmetic for multiple rooms and L-shapes automatically once you enter your measurements above.
Worked example
A bedroom measures 12 ft by 14 ft.
Area = 12 × 14 = 168 square feet.
In square metres: 168 × 0.092903 ≈ 15.61 m².
With a 10% waste factor for flooring: 168 × 1.10 = 184.8 square feet of material to order.
Frequently asked questions
How do I measure an L-shaped room?
Split the room into two rectangles at the corner of the L. Measure the length and width of the main rectangle, then the length and width of the smaller section that sticks out, and add the two areas together. If instead you are working around a built-in feature such as a fireplace hearth, measure that section separately and subtract it from the main rectangle. The calculator above has an "Add L-shape" option on each room row that does this addition or subtraction for you.
How do I convert square feet to square metres?
Multiply square feet by 0.092903 to get square metres, or divide by 10.7639. For example, 168 square feet is about 15.61 square metres. Switch the unit toggle above the room table to see every measurement and result converted automatically.
How much waste should I add for flooring?
A common rule of thumb is 10 percent extra for straightforward rectangular rooms, which covers cuts and the occasional mistake. Complex layouts, diagonal installation patterns, or materials with a repeat pattern like some tile or hardwood often need 15 to 20 percent. Check your flooring manufacturer's guidance for the specific product you are buying.
Does square footage include closets?
For flooring, paint, or material estimates, include closets and any enclosed space you plan to cover, since you still need material for that floor or those walls. For official real estate listings, standards vary by region; many appraisers use ANSI Z765 guidelines, which include closets but exclude unfinished areas such as garages and unfinished basements.