Square footage is the number every home project starts with — flooring, paint, rent comparisons, landscaping, real estate listings. This square footage calculator measures rectangular or circular spaces in any units and turns the area into a material cost estimate with a price per square foot.
How to calculate square footage
For a rectangle, multiply length × width: a 12 × 14 ft room is 168 sq ft. For circles — patios, fire pits, above-ground pools — it's π × radius²: a 10 ft diameter circle is π × 5² ≈ 78.5 sq ft. Enter feet or meters; results show square feet with metric and square-yard conversions.
Odd-shaped rooms: divide and add
L-shaped or irregular spaces are just rectangles in disguise. Split the floor plan into rectangles (and the odd triangle — ½ × base × height), measure each, and add them up. An L-shaped room that's a 12×10 plus an 8×6 wing is 120 + 48 = 168 sq ft. Measure wall-to-wall at floor level, not along baseboards.
Estimating flooring and material cost
Multiply the area by the price per square foot, then add 5–10% waste for cuts (more for diagonal layouts or patterned material). At $4.50/sq ft, that 168 sq ft room costs about $756 in material, or ~$830 with 10% waste. The same math prices turf, mulch, decking and countertops.
Related project tools
Converting between sq ft, sq m, acres and hectares? Use the area converter. Buying by the tile or the gallon instead of the square foot, the tile calculator and paint calculator take it from here.