How square footage is calculated
area = length × width × number of equal areasMetric dimensions convert to square feet using 1 square meter = 10.7639104167 square feet before any waste allowance or cost is applied.
Square footage calculator
Calculate the area of a room, lot, wall, or any rectangular surface, then estimate material cost from a price per unit area.
Enter the dimensions
For an L-shaped or irregular space, split it into rectangles and add an area for each.
A starting point for any project
Use this calculator for a quick area or real-estate figure, or as the first step before a more specific calculator — flooring, tile, paint, drywall, or sod — that applies product coverage and rounds to whole packages.
Worked example
A 15 ft × 12 ft room
Measured area15 × 12 = 180 ft²
Square yards180 ÷ 9 = 20 yd²
Square meters180 ÷ 10.7639 = 16.72 m²
With 10% waste180 × 1.10 = 198 ft² of purchase coverage
Measuring irregular areas without double-counting
Sketch the space and divide it into non-overlapping rectangles. Measure each rectangle, calculate its area separately, and add the results. For an L-shaped room, the two rectangles should meet at an edge rather than overlap. Measure closets, alcoves, islands, and permanent exclusions according to what the material will actually cover.
Keep measured area and purchase area separate. Property and room area normally use the measured figure; waste belongs only in a material order.