Percentage API
Everyday percentage maths as an API. Four clear operations: what is X% of a value (15% of 200 = 30); what percentage one number is of another (30 is 15% of 200); the percentage change between two numbers, with the direction and the raw difference (200 → 250 is a 25% increase); and applying a percentage increase or decrease to a value (200 + 15% = 230). Handy for discounts, tips and tax, growth and KPI deltas, progress bars, dashboards and quick spreadsheet-style sums — without writing a formula. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 5 endpoints. A focused calculator, distinct from a general math-expression engine.
api.oanor.com/percentage-api