How do I calculate square footage?

Multiply the length by the width using the same unit. A space 10 ft by 12 ft is 120 ft². The calculator does this and also shows the area in square meters.

How do I convert square meters to square feet?

Multiply the area in square meters by about 10.7639, because one foot is 0.3048 meters and areas convert by the square of that factor. The calculator converts automatically.

What is the difference between area and perimeter?

Area is the surface inside the shape, found by multiplying length by width. Perimeter is the distance around the edge, found by adding the sides.

How do I find the area of an L-shaped room?

Split it into rectangles, work out the area of each, and add them. This calculator handles one rectangle at a time.

Which units can I use?

Meters, feet or yards. The area is shown in the square of the unit you pick, and also converted to the other major unit.

Can I share a calculation?

Yes. Use Share to copy a link that reopens the calculator with the same length, width and unit.

Square footage calculator

Enter the length and width and pick a unit. The calculator shows the area in that unit squared, plus the same area in the other major unit, as you type.

Multiply length by width to get the area. The calculator does this for you and also converts the result between square meters and square feet.

Length

Width

Unit

Area

20 m²

Also: 215.28 ft²

The result updates as you type. The rectangle preview keeps the length-to-width proportions of your space, and the second line shows the area converted to the other unit.

How does it work?

Length and width must use the same unit. The area is in that unit squared.

Area formula

\text{area} = \text{length} \times \text{width}

length: The length of the space.
width: The width of the space.

A room 5 m by 4 m has an area of 20 m² (about 215.3 ft²).

Method & sources

The space is a simple rectangle, so the area is length times width. Length and width are measured in the same unit; the area is in that unit squared. Conversions use the exact definitions 1 ft = 0.3048 m and 1 yd = 0.9144 m, with areas as the square of those factors.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

Area measurement standards — National Institute of Standards and Technology, verified 2026-06-10

How we calculate

The space is a simple rectangle, so the area is length times width.
Length and width are measured in the same unit; the area is in that unit squared.
Conversions use the exact definitions 1 ft = 0.3048 m and 1 yd = 0.9144 m, with areas as the square of those factors.

Rounding

Areas are rounded to two decimals for display. The calculation itself uses full precision.

What this calculator does

Square footage is just the area of a rectangle: length times width. This calculator multiplies the two dimensions, shows the area in the unit you choose, and converts it to the other major unit so you can compare meters and feet at a glance.

How to use it

Enter the length of the space.
Enter the width.
Choose the unit: meters, feet or yards.
Read the area below, along with the same area in the other unit.

A worked example

A room that is 5 m long and 4 m wide has an area of 20 m². Because 1 ft = 0.3048 m, that same area is about 215.28 ft².

Square meters, feet and yards

One foot is exactly 0.3048 meters and one yard is exactly 0.9144 meters. Areas convert by the square of those factors, so one square meter is about 10.7639 square feet and one square yard is about 0.8361 square meters.

Common mistakes

Mixing units, such as a length in feet and a width in meters. Convert to one unit first.
Confusing perimeter with area. Perimeter adds the sides; area multiplies length by width.
Forgetting that an L-shaped or irregular room must be split into rectangles and added together.

When it's useful

Estimating flooring, paint, tiles or turf, sizing a rug or a room, and converting a listing's area between metric and imperial units.

FAQ

How do I calculate square footage?: Multiply the length by the width using the same unit. A space 10 ft by 12 ft is 120 ft². The calculator does this and also shows the area in square meters.
How do I convert square meters to square feet?: Multiply the area in square meters by about 10.7639, because one foot is 0.3048 meters and areas convert by the square of that factor. The calculator converts automatically.
What is the difference between area and perimeter?: Area is the surface inside the shape, found by multiplying length by width. Perimeter is the distance around the edge, found by adding the sides.
How do I find the area of an L-shaped room?: Split it into rectangles, work out the area of each, and add them. This calculator handles one rectangle at a time.
Which units can I use?: Meters, feet or yards. The area is shown in the square of the unit you pick, and also converted to the other major unit.
Can I share a calculation?: Yes. Use Share to copy a link that reopens the calculator with the same length, width and unit.

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