How to Measure a Room
- Sketch the floor. Mark doorways, closets, alcoves and any changes in direction. Label the sections you want included in the flooring project.
- Measure at floor level. Record the length and width of each rectangular section. Keep the tape straight and use the same units for both dimensions.
- Add each rectangle. Enter one row per room or section. Review the individual areas before using the combined total.
A 12 × 10 ft bedroom is 120 square feet. Adding an 8 × 6 ft office brings the combined area to 168 square feet. A 3 × 2 ft closet adds another 6 square feet, giving a final net area of 174 square feet.
Include closets only when their floors are part of the project. Furniture that will be moved does not reduce the room’s measured area. Permanent obstructions may affect the amount of flooring, but whether to subtract them depends on where the flooring will actually be installed.
Room Dimensions Quick Reference
Use this table to check the multiplication for common rectangular dimensions. These are example measurements, not standard room sizes. Measure your own room, including any alcoves, rather than choosing the closest row and treating it as an exact result.
| Room dimensions | Square feet | Square meters |
|---|---|---|
| 8 × 10 ft | 80 | 7.43 |
| 10 × 10 ft | 100 | 9.29 |
| 10 × 12 ft | 120 | 11.15 |
| 12 × 12 ft | 144 | 13.38 |
| 12 × 15 ft | 180 | 16.72 |
| 15 × 20 ft | 300 | 27.87 |
Decimal feet and inches are different. Twelve feet six inches is 12.5 feet, not 12.6 feet. Convert inches by dividing by 12 before entering a decimal-foot measurement. For example, 10 feet 3 inches becomes 10.25 feet.
How to Split an L-Shaped Room
Draw one line across the inside corner of the L to create two rectangles that touch but do not overlap. Measure the length and width of each rectangle, then use Add room / rectangle to enter the second section. Each part of the floor should be counted exactly once.
Rectangle B: 6 × 4 = 24 sq ft
L-shaped floor total: 120 + 24 = 144 sq ft
An alternative is to calculate the surrounding large rectangle and subtract the missing corner. Both methods give the same result when the dimensions are consistent. This calculator uses the add-sections method; enter positive, non-overlapping rectangles rather than a negative room.
The same approach works for a T-shaped space or a long hallway with a rectangular alcove. A curved bay or triangular section needs a different geometric calculation. Do not force those shapes into a rectangle unless you deliberately want an approximate allowance.
Square Feet, Square Meters and Floor Area
Total area = sum of the individual room areas
Square meters = square feet × 0.09290304
Switching units converts the entered dimensions and leaves the physical room unchanged. Area uses a squared conversion factor: converting feet to meters once is not enough to convert square feet to square meters. The calculator keeps full precision during conversion and rounds only the displayed area.
This tool measures floor area. Wall area for painting requires wall lengths and ceiling height, with door and window openings deducted where appropriate. Doors and windows are not subtracted from the floor measurement because they do not remove the horizontal surface being calculated.
Turn Floor Area into a Flooring Estimate
The result is net floor area, without a built-in material allowance. Flooring waste depends on plank or tile size, laying direction, pattern, room shape and the manufacturer’s instructions. Confirm an appropriate allowance for the selected product before purchasing.
For an arithmetic example, a 144 sq ft floor with a chosen 10% allowance needs 158.4 sq ft of coverage. If a box covers 20 sq ft, divide 158.4 by 20 and round up to 8 boxes. This example illustrates the method; it does not recommend 10% for every flooring installation.
Keep your room sketch and section measurements when requesting quotes. Suppliers may quote net measured area while ordering a larger packaged quantity. Separating those two numbers helps explain why the number on a material order is higher than the floor area displayed here.
Measurement reference: Tarkett Home room measurement guide.
Frequently Asked Questions
How do you calculate the square footage of a room?
Measure the room’s length and width in feet and multiply them together. For example, 12 feet multiplied by 10 feet gives 120 square feet. For several rooms, calculate each area separately and then add the areas. Enter inches as fractions of a foot, so 6 inches becomes 0.5 feet.
How do you calculate the square footage of an L-shaped room?
Split the floor into two rectangles without overlap. Measure each rectangle separately, multiply its length by its width and add the results. A 12 × 10 ft section plus a 6 × 4 ft section totals 144 square feet. Use a separate calculator row for each part of the L.
How many square feet is a 12×12 room?
A room measuring 12 feet by 12 feet contains 144 square feet, or approximately 13.38 square meters. This is the net rectangular floor area before any flooring allowance. If the dimensions describe the largest outside rectangle of an irregular room, divide the room into sections to obtain its actual usable floor area.
Do you subtract doors and windows when calculating square footage?
For floor square footage, door and window openings are not deducted. Measure the horizontal floor that will receive the material. For painting, wall area is a separate calculation based on wall length and height, and openings may be subtracted. This calculator’s totals describe floors, so they should not be used directly as a wall-paint estimate.