#payroll

Progressive (marginal) tax-bracket maths as an API. You supply the bracket schedule, so it works for any country, year or tax table and never goes stale, and it is entirely currency-agnostic. The tax endpoint takes an income and a schedule of threshold:rate pairs (with an optional standard deduction) and returns the total tax, the after-tax income, the effective and marginal rates, and a per-bracket breakdown showing exactly how much is taxed in each tier. The reverse endpoint solves the inverse problem — the gross income needed to take home a target net amount on the same schedule — by bisection. The brackets endpoint validates and normalizes a schedule into labelled tiers (adding a 0% tier from zero and marking the open-ended top bracket). Everything is computed locally and deterministically, so it is instant and private. It models only the schedule you provide — fold any allowances, credits or surtaxes into the brackets or the deduction yourself — and it is not tax advice. Ideal for payroll and HR tools, salary and offer calculators, fintech and budgeting apps, and any product that shows take-home pay. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is progressive-tax maths on a schedule you supply; for gross-pay period conversion use a payroll API and for loans and interest use a finance-calculator API.

api.oanor.com/taxbracket-api

Gross-pay maths as an API — the everyday salary and wage calculations, computed locally and deterministically and entirely currency-agnostic. The convert endpoint turns a pay figure given at any cadence — annual, monthly, bi-weekly, weekly, daily or hourly — into all the others, using configurable hours per week, weeks per year and days per week. The overtime endpoint computes regular, overtime (time-and-a-half by default) and double-time pay from the hours worked, with adjustable thresholds and multipliers, and reports the effective hourly rate. The raise endpoint applies a percentage or fixed raise, or works out the percentage from a new salary. The prorate endpoint pro-rates a salary by a worked fraction, or by days worked over days in the period — for joiners, leavers and part-periods. Everything is gross pay only: it deliberately excludes tax, deductions and benefits, which are jurisdiction-specific, so the maths stays exact and never goes stale. Computed locally, instant and private. Live, nothing stored. 4 endpoints. Ideal for HR and payroll tools, job boards and offer calculators, freelance and contractor rate tools, and budgeting apps. This is gross-pay maths; for loan, interest and investment maths use a finance-calculator API, and for net/take-home pay apply your local tax rules separately.

api.oanor.com/payroll-api