Area

Square Footage Calculator

Calculate room or project area from length and width, with optional waste allowance.

Measure complex rooms in sections

For L-shaped rooms, closets, alcoves or irregular spaces, divide the area into rectangles, calculate each one and add them together.

Example

A room that is 12 ft long and 10 ft wide is 120 square feet. With a 10% waste allowance for cuts, the material planning area becomes 132 square feet.

When to add waste

Add a waste allowance when the area will be used for flooring, tile, decking or other materials that require cuts. For simple room-size reporting, leave waste at 0%.

Common mistakes

Measure in one unit system and keep length and width consistent. For irregular rooms, missing a small alcove or closet can understate the order quantity.

Last reviewed: 2026-05-17

Before relying on this result

Use this calculator together with the formula, assumptions, limitations and examples on the page. If the topic involves health, tax, lending, investment, legal, safety or current-rate decisions, treat the number as an estimate and check the relevant primary source or professional guidance.

Calculator metadata last reviewed: 2026-05-14.