Paper Weight API
Paper-weight maths as an API, computed locally and deterministically. The convert endpoint converts between grammage (GSM, grams per square metre — the universal measure) and the US basis weight in pounds, which depends on the paper stock type: bond/writing (basis 17×22 in), text/book/offset (25×38), cover (20×26), index (25.5×30.5), tag (24×36) and bristol (22.5×28.5). The weight endpoint computes the mass of a single sheet, a 500-sheet ream and the M-weight (the weight of 1000 sheets in pounds) at a given grammage and sheet size — accepting dimensions in millimetres, centimetres, inches or metres, or a named size (A3–A5, letter, legal, tabloid). The stocks endpoint is a reference of the US stock types with their conversion factors and basis sizes. Everything is computed locally and deterministically, so it is instant and private. Ideal for printing and publishing tools, stationery and packaging apps, print-shop estimators, and shipping-weight calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is paper grammage and basis weight; for general mass-unit conversion use a unit-conversion API.
api.oanor.com/paper-api
