How Income Tax Works in the UK: A Complete Guide for 2025/2026

The UK income tax system can seem complex, but understanding how it works is essential for managing your finances effectively. This guide breaks down everything you need to know about income tax in the 2025/2026 tax year.

What is Income Tax?

Income tax is a tax on the money you earn. In the UK, it's collected through the Pay As You Earn (PAYE) system if you're an employee, meaning it's deducted automatically from your salary before you receive it. Self-employed individuals pay through Self Assessment.

The Personal Allowance

Every UK resident receives a Personal Allowance — the amount you can earn tax-free each year. For the 2025/2026 tax year, the standard Personal Allowance is £12,570.

However, the Personal Allowance starts to reduce if your income exceeds £100,000. It decreases by £1 for every £2 you earn over £100,000, meaning it's completely eliminated once your income reaches £125,140. This creates the well-known "60% tax trap" for high earners.

UK Income Tax Bands (England, Wales, and Northern Ireland)

Once your income exceeds the Personal Allowance, it's taxed at different rates depending on how much you earn:

Basic Rate (20%): Applies to income between £12,571 and £50,270
Higher Rate (40%): Applies to income between £50,271 and £125,140
Additional Rate (45%): Applies to income over £125,140

Scottish Income Tax Bands

Scotland has a different tax system with more bands. If you live in Scotland, your income tax is calculated using these bands:

Starter Rate (19%): £12,571 to £14,876
Basic Rate (20%): £14,877 to £26,561
Intermediate Rate (21%): £26,562 to £43,662
Higher Rate (42%): £43,663 to £75,000
Advanced Rate (45%): £75,001 to £125,140
Top Rate (48%): Over £125,140

Note that the Personal Allowance taper rules apply the same way in Scotland.

How Your Tax is Calculated

Your employer calculates your tax through the PAYE system using your tax code. The calculation works like this:

Your gross annual salary is divided equally across pay periods
Each pay period, a portion of your Personal Allowance is applied tax-free
The remaining income is taxed at the applicable rates
National Insurance is calculated separately

Use our free salary calculator to see exactly how much tax you'll pay on your salary.

Tax Codes

Your tax code tells your employer how much tax-free income you're entitled to. The most common code for 2025/2026 is 1257L, which gives you the standard Personal Allowance of £12,570. Other common codes include BR (all income taxed at basic rate) and D0 (all income taxed at higher rate).

Other Tax Allowances and Reliefs

You may be entitled to other tax reliefs that reduce your tax bill:

Marriage Allowance: Transfer up to £1,260 of your Personal Allowance to your spouse
Blind Person's Allowance: Additional tax-free allowance for registered blind individuals
Pension contributions: Tax relief on contributions to your pension
Charitable donations: Gift Aid allows charities to claim back tax on your donations

When Tax Rules Change

Tax bands and rates are typically reviewed annually in the Spring Budget and Autumn Statement. Changes usually take effect in April at the start of the new tax year. Always check the latest rates for your specific tax year.

Use our salary calculator to check your take-home pay for any salary amount, with accurate calculations for both UK and Scottish tax bands.