Square Footage Calculator

Square footage at a glance#

A square footage calculator finds the area of a space in square feet. For a square or rectangular room the area is length times width, so a room that is 12 feet long and 10 feet wide is 120 square feet. Keep both measurements in feet before you multiply.

Worked example: a 12 ft by 10 ft room gives 12 x 10 = 120 sq ft. To convert that to metric, multiply square feet by 0.0929, so 120 sq ft is about 11.15 square meters. For larger plots, 43,560 square feet equals 1 acre.

How do you calculate the square feet of a room?#

Measure the length and the width in feet, then multiply them: a 12 ft by 10 ft room is 12 x 10 = 120 sq ft. If a wall measures in feet and inches, convert the inches to a decimal first (6 inches is 0.5 ft) so both numbers share the same unit.

How do you find square footage for multiple rooms?#

Work out each room on its own, then add the areas together. A 12 ft by 10 ft living room is 120 sq ft and an 8 ft by 4 ft hallway is 32 sq ft, so the combined floor area is 120 + 32 = 152 sq ft. Break any L-shaped space into rectangles and add them the same way.

Enter your length and width in the calculator above for the exact square footage, with built-in unit conversion and a cost-per-square-foot estimate. Round measurements to the nearest inch, and remember that floor area can differ from the usable or listed area of a property.

How to calculate square footage#

Square footage is area measured in square feet (ft²). For a rectangle, multiply length by width with both in feet. For other shapes, switch the formula: a circle is π times the radius squared, a triangle is half the base times the height, and a trapezoid is the average of the two parallel sides times the height.

Formulas by shape#

The widget above also handles annuluses and other forms, converts between feet, inches, yards, meters, and centimeters, and can add a price per unit for a material cost estimate.

Worked examples#

Flooring for a rectangular room#

A living room that measures 20 ft by 15 ft is 20 × 15 = 300 ft². Buy flooring for that area plus a waste allowance of about 10 percent for cuts.

Paint area for a circular pool#

A circular pool 10 ft across has a 5 ft radius, so its surface is π × 5² = about 78.5 ft². Use the radius, not the diameter, in the formula.

Tiling cost for a bathroom#

A bathroom that is 9 ft by 11 ft is 99 ft². At $5 per square foot, the tile costs 99 × 5 = $495 before waste.

Tips for accurate measurements#

Keep every dimension in the same unit before you multiply, and convert inches to a decimal of a foot first (6 inches is 0.5 ft). Measure with a tape rather than estimating, and split L-shaped rooms into rectangles, then add the areas. Listed property square footage can differ from usable floor area, so measure the space yourself when material cost depends on it.

FAQ#

How do I calculate square footage for a rectangular room?#

Measure length and width in feet and multiply them. A 12 ft by 14 ft room is 12 × 14 = 168 ft².

What is the formula for the square footage of a circle?#

Area is π × radius². For a 10 ft diameter, the radius is 5 ft, so the area is π × 5² = about 78.5 ft².

Can the calculator convert between units?#

Yes. Enter feet, inches, yards, meters, or centimeters and it returns the area in square feet, or you can read it back in square meters or square inches.

How do I estimate material cost from square footage?#

Multiply the area by the price per square foot. For 200 ft² of flooring at $3 per square foot, the cost is 200 × 3 = $600.

How do I find square footage for complex shapes?#

Break the space into rectangles, triangles, or circles, find each area, and add them. For a trapezoid, average the two parallel sides and multiply by the height.