uk-paye

2025/26 UK income tax (England, Wales, Northern Ireland) and National Insurance (Class 1 employee) — the core of a take-home calculation. Pure Rust, no deps.

Same figures behind the UKMoneyCalc calculator suite.

use uk_paye::take_home;
let (net, tax, ni) = take_home(50_000.0); // GBP gross

Figures: personal allowance £12,570 (tapered above £100,000), basic 20% to £50,270, higher 40% to £125,140, additional 45% above. NI 8% between £12,570 and £50,270, 2% above. Scotland and pre-tax deductions (pension, student loan) are out of scope here.

The £100,000 to £125,140 taper, not the 40% headline rate, is what makes the next pound inside that window the most expensive one a UK employee earns. UKMoneyCalc publishes the band-by-band scan of the effective marginal rate those same frozen thresholds produce, income by income, on its marginal tax rate calculator — useful for sanity-checking income_tax and national_insurance against a second implementation before trusting either.

License: MIT