Understanding how Income Tax works in the UK is essential whether you’re employed, self-employed, or have multiple income sources. A clear grasp of how it works can help you stay on top of your finances, avoid surprises, and even save money.
The UK tax system is progressive. This means the more you earn, the more tax you pay on the additional income, not your entire income. The system applies different tax rates to different income bands, and everyone gets a tax-free Personal Allowance.
By understanding how your income fits into these bands and how thresholds and allowances affect the total tax you pay, you can make more informed decisions about things like pension contributions, savings, or even the timing of income.
What Is Income Tax?
Income Tax is a tax on the money you earn or receive, including wages, pensions, rental income, and specific benefits. In the UK, employees and self-employed individuals pay Income Tax at the same rates. However, how the tax is collected differs:
- Employees: Income Tax is usually deducted automatically through the Pay As You Earn (PAYE) system.
- Self-employed: You pay Income Tax through Self Assessment.
You must pay Income Tax if your total income exceeds the Personal Allowance in a given tax year (from 6 April to 5 April the following year).
Personal Allowance: What You Can Earn Tax-Free
Most UK residents are entitled to a Personal Allowance, the income you can earn each tax year before paying Income Tax. For the 2025/26 tax year (running from 6 April 2025 to 5 April 2026), the standard Personal Allowance is £12,570. This means if your total annual income is £12,570 or less, you won’t pay any Income Tax. This allowance applies across the UK, including Scotland.
The Tapering Allowance for High Earners
The Personal Allowance isn’t fixed for everyone. If your ‘adjusted net income’ (which is broadly your total taxable income before allowances but after certain deductions such as pension contributions) exceeds £100,000, your Personal Allowance is reduced. For every £2 you earn above £100,000, your allowance decreases by £1.
This means that if your income reaches £125,140, your Personal Allowance is reduced to zero. This tapering effect creates a particularly high marginal tax rate in the income band between £100,000 and £125,140. For income falling within this range, not only is it taxed at the higher rate (40%), but the loss of the tax-free allowance means an additional effective tax burden is applied to each pound earned.
Income Tax Bands, Thresholds and Brackets (Based on Taxable Income)
After applying your Personal Allowance, the remaining amount is your taxable income. This taxable income is divided into bands, each taxed at a different rate. For the 2025/26 tax year in England, Wales, and Northern Ireland, the Income Tax bands, thresholds, and brackets based on taxable income are as follows:
| Tax Band | Taxable Income Range | Tax Rate |
|---|---|---|
| Basic Rate | Up to £37,700 | 20% |
| Higher Rate | £37,701 to £125,140 | 40% |
| Additional Rate | Over £125,140 | 45% |
Once your Personal Allowance (£12,570) is deducted from your total income, the remaining taxable income is taxed at the above rates.
To clarify commonly used terms:
- Threshold: The income level where a new tax rate begins.
- Bracket/Band: The income range taxed at a particular rate.
Understanding these thresholds helps determine how much of your income falls into each tax bracket and is essential for accurate tax calculations and financial planning.
Note: Scotland has its own Income Tax bands and rates for earned income.
How UK Income Tax Is Calculated – With Step-by-Step Examples
Calculating your Income Tax liability is a straightforward process:
- Determine Gross Income: Calculate your total income from all sources before tax or deductions.
- Calculate Personal Allowance: Determine your applicable Personal Allowance. Remember, it reduces if your adjusted net income is over £100,000 and is £0 if your income is £125,140 or more.
- Calculate Taxable Income: Subtract your Personal Allowance from your Gross Income. If the result is negative, your taxable income is £0.
- Apply Tax Rates to Bands: Apply the relevant Income Tax rates (20%, 40%, 45%) to the portions of your taxable income that fall into each corresponding band.
- Sum the Tax: Add up the tax calculated for each band to find the total Income Tax you need to pay (tax you pay).
The calculation is best illustrated with examples:
Example 1: Gross Income £10,000
In this example, the individual earns £10,000 in the 2025/26 tax year. No Income Tax is due since this amount is below the Personal Allowance of £12,570. The tax-free Personal Allowance covers all the income, meaning the individual pays no Income Tax for the year. This example demonstrates how low earners benefit from the Personal Allowance and do not pay any Income Tax.
| Description | Amount (£) | Tax Rate | Tax Due (£) |
|---|---|---|---|
| Gross Income | 10,000 | — | — |
| Personal Allowance | 12,570 | — | — |
| Taxable Income | 0 | — | — |
| Income Tax Due | — | — | 0 |
Example 2: Gross Income £30,000
In this example, the individual earns £30,000 during the 2025/26 tax year. After applying the full Personal Allowance of £12,570, the remaining income is taxed entirely at the basic rate of 20%.
This example highlights how someone on a modest income pays tax only at the basic rate, with a significant portion of their income remaining tax-free due to the Personal Allowance.
| Description | Amount (£) | Tax Rate | Tax Due (£) |
|---|---|---|---|
| Gross Income | 30,000 | — | — |
| Personal Allowance | 12,570 | — | — |
| Taxable Income | 17,430 | — | — |
| Basic Rate: Entire £17,430 | 17,430 | 20% | 3,486 |
| Total Income Tax Due | — | — | 3,486 |
Example 3: Gross Income £60,000
In this example, the individual earns £60,000 in the 2025/26 tax year. After applying the full Personal Allowance of £12,570, the remaining income is split across two tax bands. Part of the income is taxed at the basic rate of 20%, while the portion that exceeds the basic rate threshold is taxed at the higher rate of 40%.
The example illustrates how income above a certain level begins to attract higher tax rates, even though the Personal Allowance still offers some relief.
| Description | Amount (£) | Tax Rate | Tax Due (£) |
|---|---|---|---|
| Gross Income | 60,000 | — | — |
| Personal Allowance | 12,570 | — | — |
| Taxable Income | 47,430 | — | — |
| Basic Rate: First £37,700 | 37,700 | 20% | 7,540 |
| Higher Rate: £37,701 to £47,430 (£9,730) | 9,730 | 40% | 3,892 |
| Total Income Tax Due | — | — | 11,432 |
Example 4: Gross Income £115,000
In this example, the individual earns £115,000 in the 2025/26 tax year. Since their income exceeds £100,000, their Personal Allowance is gradually reduced. The reduction is calculated as £1 for every £2 over £100,000.
| Description | Amount (£) | Tax Rate | Tax Due (£) |
|---|---|---|---|
| Gross Income | 115,000 | — | — |
| Income over £100,000 | 15,000 | — | — |
| Personal Allowance Reduction (£15,000 ÷ 2) | 7,500 | — | — |
| Applicable Personal Allowance | 5,070 | — | — |
| Taxable Income | 109,930 | — | — |
| Basic Rate: First £37,700 | 37,700 | 20% | 7,540 |
| Higher Rate: £37,701 to £109,930 (£72,230) | 72,230 | 40% | 28,892 |
| Total Income Tax Due | — | — | 36,432 |
Example 5: Gross Income £160,000
In this example, the individual has a gross income of £160,000 for the 2025/26 tax year. As their income exceeds £125,140, they are not entitled to any Personal Allowance, making the full £160,000 taxable.
| Description | Amount (£) | Tax Rate | Tax Due (£) |
|---|---|---|---|
| Gross Income | 160,000 | — | — |
| Personal Allowance | 0 | — | — |
| Taxable Income | 160,000 | — | — |
| Basic Rate: First £37,700 | 37,700 | 20% | 7,540 |
| Higher Rate: £37,701 to £125,140 (£87,440) | 87,440 | 40% | 34,976 |
| Additional Rate: £125,141 to £160,000 (£34,860) | 34,860 | 45% | 15,687 |
| Total Income Tax Due | — | — | 58,203 |
Planning Your Finances Around UK Tax
Effective financial planning can minimise tax liability. Increasing pension contributions reduces taxable income, potentially keeping an individual within a lower rate tax band. For example, an income of £60,000 reduced by a £5,000 pension contribution lowers taxable income to £55,000, decreasing higher rate tax.
Taxpayers can remain below key taxation thresholds by strategically managing income sources, such as balancing salary and dividends if self-employed. Professional advice is recommended for those nearing £100,000 to navigate the Personal Allowance reduction and optimise tax efficiency.
Don’t Forget About National Insurance
National Insurance (NI) is separate from Income Tax but also deducted from earnings. It helps fund the state pension and other benefits.
Both employees and the self-employed pay NI, although the rates and methods differ. Like Income Tax, it affects your take-home pay, so it’s essential to factor it in when planning your finances.
To help you understand National Insurance, we offer detailed articles:
- Understanding National Insurance Contributions for Employees – Learn how NI is calculated through PAYE and how it affects your pay.
- Self-Employed National Insurance – A guide covering Class 2 and Class 4 NI, including thresholds and how it’s reported via Self Assessment.
Try Our Tax Calculators
Our website features free tax calculators for both employees and the self-employed. These tools are designed to help you quickly estimate how much Income Tax and National Insurance you’ll pay for the 2025/26 tax year based on your income.
- Employee Tax Calculator – Enter your gross annual income to see your Income Tax, NI contributions, and take-home pay.
- Self-Employed Tax Calculator – Designed for freelancers, sole traders, and contractors. Estimate your tax bill based on your business profits.
These calculators use the latest tax bands and allowances and give you a clear breakdown of your deductions.
Conclusion
Understanding UK Income Tax, including knowledge of the Personal Allowance, tax thresholds, and Income Tax rates, empowers taxpayers to manage their finances effectively.
For the 2025/26 tax year, commencing on 6 April, most individuals benefit from a £12,570 tax-free allowance, with subsequent earnings taxed at 20%, 40%, or 45%, depending on income levels.
Taxpayers should consult a tax advisor or HMRC’s official resources for further guidance.
