UK Marginal Tax & Personal Allowance Intelligence
Private, client-side tools modeling the UK's statutory tax thresholds: the £100k Personal Allowance taper, the High Income Child Benefit Charge (HICBC), and salary sacrifice optimization.
Marginal Tax & 60% Taper Calculator
Calculate your exact effective marginal tax rate between £100,000 and £125,140 where the personal allowance taper doubles income tax. Model pension sacrifice to reclaim lost allowance.
More Calculations Coming Soon
New tax and salary sacrifice planning tools are currently in development.
100% Client-Side Privacy
All salary numbers, bonuses, and family details execute locally in your browser session. No databases, no telemetry, no tracking.
Arbitrary Decimal Math
Eliminates floating-point rounding errors with exact decimal calculation. Every pound and penny matches statutory HMRC rounding.
Statutory Transparency
Every calculation cites primary UK tax legislation including ITA 2007 s 35/58 and ITEPA 2003 s 681B. Verified with automated golden vectors.