Tax & HMRC
Tax-year dates, codes and the rules behind a second income.
The rules HMRC applies to your income sit behind most of the site's calculators: which tax year you're in, which Income Tax band your earnings fall into, and how a second job or side income gets taxed differently from your main one. UK Tax Year Dates is the reference point the other two guides work from.
All 5 Tax & HMRC guides
New job and taxed 20% on everything? BR, BRX and emergency tax codes explained
Your first payslip in a new job shows 20% tax on every pound. Here is how to read the code behind it, what BR, BRX and the emergency codes actually take from the same month’s pay, and how the refund reaches you.
Read guideSecond Job on a BR Tax Code: Why You Might Owe 40% Tax
A BR code taxes your second job at 20%. If your total pay tops £50,270 you owe the rest. 2026/27 worked example, how HMRC collects it and how to avoid it.
Read guideUK Income Tax Bands 2026/27: England, Wales, NI and Scotland
The 2026/27 Income Tax bands and rates for England, Wales and Northern Ireland, how Scotland's six bands differ, and the thresholds where your marginal rate jumps.
Read guideSecond Job Tax Explained: How HMRC Taxes a Second Job or Side Income
Why a second payslip is often taxed at BR, how HMRC splits your Personal Allowance across two jobs, and why National Insurance and self-employed side income work differently.
Read guideUK Tax Year Dates: Key Deadlines for 2026/27
When the UK tax year starts and ends, what changes on 6 April, and the key Self Assessment deadlines to know for the 2026/27 tax year.
Read guideWhere to start
If you want the foundations, UK Income Tax bands and rates is the place to begin. Almost every other guide here assumes you know where the Personal Allowance and the higher-rate threshold sit.
Three guides deal with the problem that brings most people to this section: being taxed more than expected after a change of job. BR, BRX and emergency tax codes explains why a new job can tax everything you earn at 20% with no Personal Allowance. Second job tax explained covers how HMRC taxes a second job or side income generally, and Second job on a BR tax code deals with the narrower case where a BR code on a second job leaves you underpaying and facing a 40% bill later.
UK tax year dates covers the deadlines: when the tax year starts and ends, and when Self Assessment and payments on account fall due.
The Autumn Budget 2026 guide covers what is confirmed and what is only speculation ahead of 28 October, and will be updated with the actual measures on the day.