Square Footage Calculator
Find the area of a room or lot in square feet and square meters, for rectangles, circles, triangles, and multiple spaces.
Enter the dimensions to find the area.
How to use the square footage calculator
Pick the shape that matches the space, choose feet or meters, and type the dimensions. A rectangle needs a length and a width, a circle needs a radius, and a triangle needs a base and a height. The area appears as you type, shown in both square feet and square meters.
For an L-shaped room or a whole floor, break the space into simple shapes, add each one, and the tool keeps a running total. The total stays correct if you switch units partway through, so you can mix a measurement in feet with the metric readout you need at the store.
Area formulas by shape
A rectangle is length times width, the formula behind most room measurements. A square is the same rule with equal sides. A triangle is base times height divided by two, which suits a gable wall or a corner section of a yard.
A circle is pi times the radius squared, where the radius is the distance from the center to the edge, or half the full width across. For a circular patio measured at 10 feet across, the radius is 5 feet, so the area is about 78.5 square feet.
Where square footage matters
Almost every material estimate starts with area. Flooring, tile, and carpet are priced and sold by the square foot or square yard, and paint coverage is rated per square foot. Get the area right and the rest of the project math follows cleanly.
Square footage also drives real estate listings, rent calculations, and property tax assessments. Knowing how to measure it yourself lets you check a listing figure or work out a price per square foot before you sign anything.
Feet, meters, and accurate measuring
One square meter is about 10.76 square feet, so the two readouts will look very different for the same room. The tool converts between them exactly, using the definition that one foot equals 0.3048 meters, so you never have to round by hand.
Measure to the nearest inch and take each dimension twice to catch a slip. For rooms that are not perfectly square, measure the longest and widest points and treat the space as a rectangle, then trim back any alcoves as separate negative areas if you need precision.
Frequently asked questions
- How do I calculate the square footage of a room?
- Measure the length and the width in feet and multiply them. A room that is 10 feet by 12 feet is 120 square feet. For rooms that are not rectangular, split them into simple shapes and add the areas together.
- How do I find the area of a circular space?
- Measure the radius, the distance from the center to the edge, and use pi times the radius squared. A circle with a 5-foot radius covers about 78.5 square feet. If you only know the full width across, halve it to get the radius.
- How many square feet are in a square meter?
- One square meter equals about 10.76 square feet. The calculator shows both units at once and converts using the exact definition that one foot is 0.3048 meters, so the figures stay precise.
- How do I measure an L-shaped or irregular room?
- Divide the space into rectangles or triangles, calculate each area, and add them. This tool lets you add several areas and keeps a running total, which makes irregular layouts straightforward.
- Should I add extra for flooring or paint?
- Yes. The square footage is the bare area to cover. Materials need a waste allowance for cuts and mistakes, usually around 10 percent, which the matching paint, tile, and carpet calculators add for you.