Guides
How your payslip actually works.
Short, accurate explainers behind every number the calculator shows, written from the GOV.UK sources, not from other calculators.
How income tax works
The personal allowance, the bands, the £100k taper, and why Scotland is different.
Read the guide →National Insurance explained
What Class 1 contributions are, the 8% and 2% rates, and the employer NI you never see.
Read the guide →Student loan repayments
Plans 1, 2, 4, 5 and postgraduate: thresholds, the 9% rule, and how payroll rounds.
Read the guide →Tax codes, decoded
What 1257L, K codes, BR, D0 and the emergency suffixes actually do to your pay.
Read the guide →How bonuses are taxed
No special rate, just your marginal one. Worked examples, and the sacrifice escape.
Read the guide →The £100k tax trap
The 62% taper zone, the childcare cliff, and the pension move that unwinds both.
Read the guide →