Add up square footage the way rooms actually come: as a list of rectangles, triangles, and circles. Each area computes as you type; the total — with its exact metric equivalent — updates live. All measurements in feet.
How to calculate square footage
- Measure each area’s dimensions in feet (to the nearest inch is plenty: 6 in = 0.5 ft).
- Add an area per shape — split L-shapes and odd rooms into rectangles/triangles at the corners.
- Read each row’s area and the live total, with square meters alongside.
- Buying materials? Carry the total into the paint calculator or add a waste margin for flooring.
The formulas
Rectangle: length × width. Triangle: base × height ÷ 2 (height is the perpendicular distance, not the sloped side). Circle: π × diameter² ÷ 4 — measure across the widest point. Everything else decomposes into those three: a bay window is a rectangle plus a triangle or half-circle; a hallway with a jog is two rectangles.
Measuring tips that save a re-measure
Measure at floor level along the baseboard — walls lean, floors don’t. For carpeted stairs, each tread+riser pair is roughly 3 sq ft of surface at standard dimensions, counted separately from the floor plan. And write down the room name as you go (the rows here have a name field) — a total you can’t audit is a total you’ll re-measure. Note the listing-convention caveat in the FAQ: what counts toward a home’s advertised square footage is a standards question, not a math one.
Private by design
Everything is computed on your device as you type — no measurements are uploaded or stored. Converting an existing figure instead? Square meters to square feet handles the straight conversion.