Square Footage & Area
Area of a room, floor, or surface built from rectangles, triangles, circles, and trapezoids — openings subtracted — in square feet, yards, and metres at once.
Add the pieces,
take out the holes.
How an irregular space becomes a checkable list of shapes, and what the number does not tell you.
Sections and formulas
Split the space into sections you can measure: rectangle (length × width), triangle (½ × base × height, or Heron's formula from three sides), circle and half circle (π × radius²), trapezoid (½ × (a + b) × height), ellipse (π × half-width × half-height). Mark stairwells, columns, or islands as subtract. The net area is everything added minus everything subtracted; each section's own area is listed so a wrong measurement is easy to spot.
Units and conversion
Every dimension is converted to metres first (1 ft = 0.3048 m exactly), so the square metres, square feet, square yards, square inches, and square centimetres shown are the same quantity: 1 ft² = 144 in² = 0.09290304 m², 1 yd² = 9 ft², 1 m² = 10.7639 ft². Switching the unit system converts what is shown; nothing you typed is replaced.
What the area does not decide
This is plane area. Sloped surfaces are larger than their footprint (a pitched roof needs its slope factor), and the material you buy also depends on sheet, plank, or tile sizes, layout, and cutting waste — the waste allowance here is yours to set; no figure is assumed. Prices are whatever you enter. Inputs stay in your browser; the same four anonymous usage counts as the rest of the site apply.