# How to calculate room size in square feet

Canonical URL: https://www.evenoutapp.com/tools/how-to-calculate-room-size
Updated: 2026-10-06

Measure the length and width of the floor in feet, wall to wall, and multiply them. A 14 by 12 foot room is 168 square feet. For an L-shaped room, split it into rectangles, find each area and add them: a 6 by 4 foot section brings the room to 192 square feet. Decide separately whether the closet counts.

Key points:
- Room size is length times width in feet. A room 14 feet long and 12 feet wide is 14 × 12 = 168 square feet.
- Turn inches into decimal feet by dividing by 12. Six inches is 0.5 feet and nine inches is 0.75 feet.
- Split an L-shaped room into two rectangles and add them: 168 + (6 × 4) = 192 square feet.
- Count closets in every room or in none. Counting a 12 square foot closet in one room only adds $42.15 to that room's share of a $2,880 rent.
- Multiply square feet by 0.0929 for square meters. 192 square feet is about 17.8 square meters.

## When do you need to calculate room size?

The usual reason is splitting rent by bedroom. [How to split rent by room size](https://www.evenoutapp.com/guides/how-to-split-rent-by-room-size) needs one number per bedroom, and the numbers only compare fairly when every room is measured the same way. Once you have them, the rent split calculator by room size turns them into dollar amounts. This page covers the measuring.

## How do you calculate the size of a room?

Multiply the length of the floor by its width, both in feet, and the result is square feet.

1. **Measure the length.** Run a tape along the floor from one wall to the opposite wall and write it down.
2. **Measure the width.** Measure the other way across, from a wall at a right angle to the first.
3. **Multiply the two.** A room 14 feet long and 12 feet wide is 14 × 12 = 168 square feet.

A tape reads in feet and inches, but the multiplication wants decimal feet. Divide the inches by 12, so 12 feet 6 inches is 12 + 6 ÷ 12 = 12.5 feet. Two decimals is enough: rounding 4 inches to 0.33 feet changes the area by less than a tenth of a square foot, even against a 14 foot wall. The table gives common inches as decimal feet.

| Inches | Decimal feet |
|---|---|
| 3 | 0.25 |
| 4 | 0.33 |
| 6 | 0.5 |
| 8 | 0.67 |
| 9 | 0.75 |
| 10 | 0.83 |

## How do you measure an L-shaped or irregular room?

Split the floor into rectangles that do not overlap, find each area and add them. Say the 14 by 12 foot room has a 6 by 4 foot alcove at one end. The main part is 14 × 12 = 168 and the alcove is 6 × 4 = 24, so the room is 192 square feet. In the calculator, the alcove goes in the second section boxes.

Cut the same floor the other way as a check. A 6 by 16 foot strip along the alcove end is 96 and the remaining 8 by 12 foot block is 96, which is 192 again. If two cuts disagree, one tape reading is wrong.

A corner that is cut off at an angle is a triangle, and its area is half of base times height. Legs of 3 feet and 3 feet remove ½ × 3 × 3 = 4.5 square feet. A bay window or a curved wall is easiest to treat as the nearest rectangle, as long as every room follows the same habit. For three or more sections, work out each one and add them by hand.

## Should the closet count?

Count closets in every room or in none, and decide before anyone measures. The calculator shows the room with and without the closet. A closet 6 feet wide and 2 feet deep is 12 square feet, so the example room is 192 without it and 204 with it.

The choice moves money. Say the rent is $2,880 and the three bedrooms are 192, 156 (12 by 13) and 132 (11 by 12) square feet. They total 480, so the rent is $6.00 a square foot and the rooms pay $1,152, $936 and $792. Count the closet in the first room only and the total becomes 492. That room now pays $2,880 × 204 ÷ 492 = $1,194.15, which is $42.15 more, and the other two pay $913.17 and $772.68.

## How do you convert square feet to square meters?

Multiply square feet by 0.0929. The exact factor is 0.09290304, because one foot is 0.3048 meters. The example room is 192 × 0.09290304 = 17.84 square meters, which the calculator shows as 17.8. Going the other way, multiply square meters by 10.764.

## What mistakes skew the numbers?

- **Measuring to a different point in each room.** Measure to the surface of the wall in every room, not the middle of the wall in one and the inside edge in another.
- **Rounding every measurement up.** Rounding 11.6 by 12.4 feet up to 12 by 13 turns 143.84 square feet into 156, which is about 12 square feet too many.
- **Trusting one reading when the walls are out of square.** A room that is 12 feet wide at one end and 12.5 at the other, and 14 feet long, is 12.25 × 14 = 171.5 square feet. A single reading of 12 would say 168.
- **Counting shared space.** Only bedrooms go into a rent split by room size. Hallways and the kitchen stay out.

With a size for each bedroom, put them into the rent split calculator by room size. In [EvenOut](https://www.evenoutapp.com/), choose Shares in the split picker for the rent expense and type the square feet as the shares: 192, 156 and 132 show $1,152, $936 and $792 under the three names. If one room should pay extra for a bathroom or a view, [how much more the master bedroom should pay](https://www.evenoutapp.com/guides/how-much-more-should-the-master-bedroom-pay) shows how to put a dollar price on those features.

## Frequently asked questions

### How accurate does the measurement need to be?

Within an inch or two is plenty. Being 2 inches (0.17 feet) off on one wall of a 12 by 14 foot room changes the area by about 2 square feet, about 1% of 168. Use the same tape and the same rule in every room so the comparison stays fair.

### How do I calculate room size if I measured in meters?

Multiply the two lengths in meters. A room 4.2 meters by 3.6 meters is 15.12 square meters. To see it in square feet, multiply by 10.764, which gives about 162.8 square feet. For a rent split the unit does not matter if every room uses the same one.

### Can I use the square footage in a lease or listing?

Only if it lists each bedroom on its own. One figure for the whole home says nothing about how the bedrooms compare with each other. Measure the bedrooms yourselves so every room follows the same rule.