How to Calculate Square Footage

For a simple rectangular room: length × width. For a triangular section: base × height ÷ 2. For a circular area like a round patio: π × radius².

Irregular rooms are just combinations of these shapes. Break the space into rectangles, triangles, and circles you can measure individually, calculate each one, and add them together — this is exactly what the multi-area Square Footage Calculator does for you.

Always measure at the longest point of each wall, not along baseboards or trim, which can shave inches off your total.

Keep in mind that flooring material needs the finished floor area, while paint and drywall need wall area instead — a separate calculation using height rather than a second floor dimension. Don't reuse a room's square footage for a wall material by mistake.