Square Footage Calculator (Square Feet, Meters & Yards)

Square footage is just area — the amount of flat surface inside a boundary — measured in one-foot squares. For a rectangular room, wall, or slab you multiply length by width, and the answer is how many one-foot tiles it would take to cover the surface. A 12 ft by 10 ft room is 120 square feet because that is how many of those foot-square tiles fit inside it. Measure both sides in the same unit, keep the numbers honest to the nearest inch, and the multiply does the rest.

Round areas work a little differently: instead of length times width you use the circle formula, area equals pi times the radius squared. Enter the diameter — the full distance across — and the calculator halves it to get the radius, squares that, and multiplies by pi (about 3.1416). Flip the toggle to metric and the same surface comes back in square meters, with square yards shown too because flooring, sod, and concrete are often priced by the yard. Every figure is the same physical area, just counted in different-sized squares.