Square Footage Calculator is a free browser tool for measuring rooms, plots and roofs — no account needed.

The site ships six calculators, each aimed at a different measuring job:

Homepage — add several rooms at once and get one running total for the whole house.

Sq Ft Calculator — type feet and inches, read back square feet, square yards and square meters.

Area Calculator — find the area of a plot, circle, triangle or trapezoid, in feet, meters or yards.

Acre Calculator — convert acres to square feet, square meters and hectares, and see how big an acre actually is.

Roof Pitch Calculator — rise and run in, pitch (x/12), degrees, percent slope and the area multiplier out.

Roof Square Footage Calculator — turn house footprint and pitch into roof area, roofing squares and shingle bundles.

Every page also carries a plain-English guide: how to measure a room, how to measure a house, and a room-size reference chart. Everything runs client-side in the browser — no sign-up, no install, no email.