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Room Square Footage Calculator

Square footage for a rectangular room is calculated as length times width in feet. For L-shaped rooms, divide the space into two rectangles and add their areas. For circular rooms, the formula is pi times the radius squared. Select a room shape and enter dimensions to calculate area in square feet, square yards, and square meters.

Quick Answer

A rectangular room measuring 12 feet by 10 feet has an area of 120 square feet (13.33 square yards, or 11.15 square meters).

Common Examples

Input Result
Rectangle: 12 ft x 10 ft 120.00 sq ft / 13.33 sq yd / 11.15 sq m
Rectangle: 15 ft x 20 ft 300.00 sq ft / 33.33 sq yd / 27.87 sq m
L-shape: 12x10 + 8x6 168.00 sq ft / 18.67 sq yd / 15.61 sq m
Circle: 14 ft diameter 153.94 sq ft / 17.10 sq yd / 14.30 sq m

How It Works

Rectangular Room: Area = Length x Width

Most rooms are rectangular. Measure the length and width in feet, then multiply. A room that is 12 feet long and 10 feet wide has an area of 120 square feet.

L-Shaped Room: Area = (Length1 x Width1) + (Length2 x Width2)

For an L-shaped room, mentally divide it into two rectangles. Measure each rectangle separately and add the two areas together. The dividing line can be drawn wherever it creates two clean rectangles.

Circular Room: Area = π x (diameter / 2)^2

For round or circular rooms, measure the diameter (the distance across the widest point). Divide by 2 to get the radius, then apply the circle area formula. A room with a 14-foot diameter has an area of approximately 153.94 square feet.

Unit Conversions

  • Square yards = square feet / 9 (useful for carpet and flooring estimates)
  • Square meters = square feet x 0.092903 (for metric conversions)

One square yard equals 9 square feet (3 feet x 3 feet). One square meter equals approximately 10.764 square feet.

Measuring Tips

For the most accurate results, measure at floor level along the longest wall for each dimension. Include closets or alcoves separately if they are not part of the main rectangle. For irregularly shaped rooms beyond the three shapes provided here, break the room into simpler shapes, calculate each one, and add them together.

Worked Example

For a rectangular room measuring 15 feet by 20 feet: Area = 15 x 20 = 300 square feet. In square yards: 300 / 9 = 33.33 square yards. In square meters: 300 x 0.092903 = 27.87 square meters. For an L-shaped room with Section 1 at 12 x 10 feet and Section 2 at 8 x 6 feet: Area = (12 x 10) + (8 x 6) = 120 + 48 = 168 square feet, or 18.67 square yards, or 15.61 square meters.

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Frequently Asked Questions

How do I measure an L-shaped room?
Divide the L-shape into two rectangles by drawing an imaginary line where the shape changes direction. Measure the length and width of each rectangle separately, calculate the area of each, and add them together. It does not matter where exactly you draw the dividing line, as long as the two rectangles cover the entire floor area without overlapping.
How do I convert square feet to square yards?
Divide the square footage by 9. One square yard equals 9 square feet (3 ft x 3 ft). For example, a 180 square foot room is 180 / 9 = 20 square yards. This conversion is commonly used when purchasing carpet or other flooring sold by the square yard.
What if my room is not a perfect rectangle?
Most rooms have small irregularities. For rooms that are close to rectangular, measure the longest length and widest width for a reasonable estimate. For rooms with bay windows, alcoves, or bump-outs, break the room into multiple rectangles, calculate each area, and add them together.
How much flooring do I need for a room?
Start with the calculated square footage. Most flooring contractors recommend adding 5% to 10% extra for waste from cuts and fitting. For example, a 200 square foot room would need approximately 210 to 220 square feet of material.
Is square footage measured from the inside or outside of walls?
For room square footage (usable floor space), measure from the inside faces of the walls. Exterior square footage or gross building area is measured from the outside of exterior walls and is typically larger. Real estate listings often use gross area, which includes walls and other non-usable space.

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