Square Footage Calculator for Rooms and Shapes
Pick the room shape, enter its measurements and how many identical rooms you have. You get the area in square feet and square metres. Rectangle: A is length and B is width. Triangle: A is base and B is height. Circle: A is diameter. L-shape: A and B are the outer length and width, C and D the size of the missing corner.
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Formula
- Rectangle:
A x B - L-shape:
A x B - C x D(C must be less than A and D less than B) - Triangle:
A x B / 2 - Circle:
pi x (A / 2)^2 - Total:
area of one room x number of rooms - 1 ft = 0.3048 m, so
1 ft2 = 0.09290304 m2
Assumptions
- All measurements are in the same unit, feet or metres, and rooms are flat floors.
- Measure wall to wall at the longest points; for irregular rooms split the plan into simple shapes and add the totals.
- Areas are rounded to two decimals.
Worked example
A 12 ft by 10 ft rectangle is 12 x 10 = 120 ft2, and 120 x 0.09290304 = 11.15 m2. An L-shaped room 20 ft by 15 ft with an 8 ft by 6 ft corner missing is 300 - 48 = 252 ft2 (23.41 m2). A 10 ft diameter circle is 3.1416 x 25 = 78.54 ft2.
Frequently asked questions
How do I calculate square footage of a room?
For a rectangle multiply length by width in feet. A 12 ft by 10 ft room is 12 x 10 = 120 square feet, which is 11.15 square metres.
How do I measure an L-shaped room?
Measure the outer length and width as if the room were a full rectangle, then subtract the missing corner. A 20 by 15 ft box less an 8 by 6 ft corner is 300 - 48 = 252 square feet.
How do I convert square feet to square metres?
Multiply by 0.09290304. 120 square feet x 0.09290304 = 11.15 square metres. To go back, multiply square metres by 10.7639. For example 20 square metres is 215.28 square feet.
How do I find the area of a triangle or circular room?
A triangle is half of base x height, so 12 ft by 9 ft is 54 square feet. A circle is pi x radius squared; for a 10 ft diameter that is 3.1416 x 25 = 78.54 square feet. Split an irregular room into these shapes and add the areas.