Square Footage Calculator

Square footage is the basic unit almost every home improvement project gets measured in, whether you're buying flooring, ordering paint, or just trying to describe a room to a contractor. For a simple rectangular room, it's just length times width, but plenty of real rooms aren't simple rectangles.

An L-shaped room, common in open floor plans, additions, and older homes with irregular layouts, can still be measured accurately by splitting it into two rectangles and adding their areas together. Picture the L shape as one larger rectangle with a smaller rectangular bite taken out of a corner, or equivalently, two separate rectangles that share an edge; either way, measuring each piece separately and adding the results gives you the true total area, which a single length-times-width measurement across the widest points would overstate.

This calculator supports both cases: a straightforward rectangle mode for simple rooms, and an L-shaped mode that asks for the dimensions of each of the two rectangles that make up the space. Measure each rectangle at its own length and width, making sure not to double-count the area where they'd overlap if you measured a single bounding box instead.

More complex room shapes, T-shapes, rooms with bay windows or angled walls, curved walls, can often be broken down the same way: divide the space into simple rectangles (or triangles, for angled sections), calculate each piece, and add them together. This "divide and conquer" approach is how contractors and flooring installers handle irregular spaces in practice, and it scales to almost any shape as long as you're willing to break it into simpler pieces first.