Paint Calculator API

Paint estimating and mixing maths as an API, computed locally and deterministically. The coverage endpoint works out how much paint an area needs — paint = area × coats ÷ spreading rate — from an area (in square metres or square feet), the number of coats and the paint's coverage (in m² per litre or square feet per US gallon, defaulting to a typical emulsion), and returns the volume in litres and US gallons and, given a tin size, the number of tins to buy. The room endpoint computes the paintable wall area of a room from its length, width and height — perimeter × height minus the door and window openings, optionally plus the ceiling — and then the paint needed, with sensible default door and window sizes you can override. The ratio endpoint splits a total volume by a mixing ratio such as 4:1 (base to hardener) or 4:1:10 (base, hardener, thinner) into each component's amount and percentage, or scales the whole mix up from one known component amount — for two-part epoxies, catalysed paints and thinning. Everything is computed locally and deterministically, so it is instant and private. Ideal for decorating, trade and DIY tools, hardware-store and paint-shop apps, estimating and quoting software, and home-improvement projects. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is paint coverage and mixing; for mulch, soil and gravel volumes use a landscaping API.