You want one number: how much income tax you'll actually owe this year. A good calculator gives you that in seconds, but only if you feed it the right figures and understand what it's doing under the bonnet.
This guide shows you how a UK income tax calculator works for the 2026/27 tax year, the bands and rates it uses, and two fully worked examples so you can sanity-check the answer yourself. It's written for sole traders, landlords and company directors who want a quick, trustworthy estimate before they speak to an accountant.
The figures here apply to England, Wales and Northern Ireland. Scotland sets its own income tax rates and bands, so if you're a Scottish taxpayer the numbers will differ.
What does a UK income tax calculator actually do?
A calculator does three things. It works out how much of your income is tax-free, splits the rest across the tax bands, and applies the right rate to each slice.
The tax-free part is your personal allowance. For 2026/27 the standard personal allowance is £12,570. Everything above that gets taxed at one of three rates, depending on which band it falls into.
The key thing to understand is that the bands are stacked, not all-or-nothing. You don't pay 40% on your whole salary the moment you cross into the higher rate. You pay each rate only on the income that sits inside that band. A good calculator handles this for you, but it's worth knowing so the result makes sense.
What are the income tax bands for 2026/27?
Here are the income tax rates and bands for England, Wales and Northern Ireland for 2026/27.
| Band | Taxable income (after personal allowance) | Rate |
|---|---|---|
| Personal allowance | First £12,570 of income | 0% |
| Basic rate | Up to £37,700 | 20% |
| Higher rate | £37,701 up to the additional-rate threshold | 40% |
| Additional rate | Taxable income above £125,140 | 45% |
In total-income terms, the higher rate starts at £50,271 and the additional rate starts above £125,140.
One trap to watch: if your adjusted net income goes over £100,000, your personal allowance is reduced by £1 for every £2 above that figure. By £125,140 it has gone completely, which is why income in that band is taxed especially heavily.
These figures come straight from HMRC's published rates for 2026/27. See the Sources list at the end.
How do you work out your income tax step by step?
Whether you use a calculator or do it by hand, the logic is the same. Follow these five steps.
- Add up your taxable income. This is your salary, profits, rental income, taxable savings and so on for the year.
- Subtract your personal allowance. For most people that's £12,570 for 2026/27. If your income is over £100,000, reduce the allowance first.
- Fill the basic-rate band. Tax the first £37,700 of what's left at 20%.
- Fill the higher-rate band. Tax the next slice, up to the £125,140 point, at 40%.
- Apply the additional rate. Tax anything above £125,140 at 45%.
Add the slices together and you have your income tax. National Insurance is calculated separately, which we'll cover in the self-employed example below.
Worked example: an employed higher earner
Illustrative example. Imagine Daniel, a salaried marketing director with a £60,000 salary in 2026/27 and no other income. He lives in England.
- Income: £60,000
- Less personal allowance: £12,570 (his income is under £100,000, so it isn't tapered)
- Taxable income: £47,430
Now we slice it across the bands:
| Slice | Amount | Rate | Tax |
|---|---|---|---|
| Basic rate | £37,700 | 20% | £7,540 |
| Higher rate | £9,730 | 40% | £3,892 |
| Total income tax | £11,432 |
The higher-rate slice is the income above £50,270 (that's £60,000 minus £50,270, which is £9,730). Daniel's total income tax for 2026/27 is £11,432. His employer will also deduct National Insurance through payroll, which a take-home pay tool will fold in.
Worked example: a self-employed sole trader
Illustrative example. Now imagine Aisha, a self-employed graphic designer with £45,000 of profit in 2026/27. Sole traders pay income tax and Class 4 National Insurance on their profits.
First, the income tax:
- Profit: £45,000
- Less personal allowance: £12,570
- Taxable income: £32,430, all within the basic-rate band
- Income tax: £32,430 x 20% = £6,486
Then the Class 4 National Insurance. For 2026/27, the self-employed pay 6% on profits between £12,570 and £50,270, and 2% above that.
- Profits in the 6% band: £45,000 minus £12,570 = £32,430
- Class 4 NI: £32,430 x 6% = £1,945.80
| Liability | Amount |
|---|---|
| Income tax | £6,486.00 |
| Class 4 National Insurance | £1,945.80 |
| Total to budget for | £8,431.80 |
So Aisha should set aside around £8,432 for her 2026/27 Self Assessment, before any payments on account. If you're a sole trader, our guidance for sole traders walks through exactly how this lands on your return.
What does the calculator often miss?
A calculator is only as good as what you tell it. In practice, the things we most often see left out are the allowances and reliefs that change the answer.
- The personal savings allowance. Basic-rate taxpayers can earn a chunk of savings interest tax-free, so not all interest is taxable. Many people declare interest they didn't need to.
- The dividend allowance. For 2026/27 the first £500 of dividends is tax-free, and dividends are taxed at their own rates. Company directors paying themselves in dividends should use a tool built for that, like our dividend tax calculator.
- Pension contributions. Higher and additional-rate taxpayers often need to claim extra relief through Self Assessment rather than getting it automatically.
- The £100,000 cliff edge. Once you cross £100,000, the tapering personal allowance pushes your effective rate up sharply. A basic calculator may not handle this well.
None of these are exotic. They're everyday items that quietly change what you owe, which is why a quick estimate and a proper review are two different things.
Which HMRC and Zmartly calculator should you use?
HMRC's own "Estimate your Income Tax for the current year" tool is built for employees who pay tax and National Insurance through PAYE. It's a solid starting point if your only income is a single salary. If you're self-employed, it points you to Self Assessment instead.
If your situation is even slightly mixed, salary plus dividends, rental income on top of a job, or profits from a side business, a single-purpose tool will fall short. That's where it pays to use a calculator matched to your income type:
- For a quick all-in estimate, try our income tax calculator.
- To see what actually lands in your pocket, use our take-home pay calculator.
Landlords in particular should be careful, as mortgage interest relief and allowable expenses change the taxable figure before any calculator even starts. Our support for landlords covers how property income is taxed.
Get your number checked, not just estimated. A calculator gives you a figure in seconds. We make sure it's the right one, and that you're not leaving relief on the table. Book a free 20-minute call with a Zmartly accountant and we'll sanity-check what you owe for 2026/27.
If you run a company, the picture shifts again, because profit can be taxed at the company level before you draw it personally. See our guidance for limited companies and our self-assessment service for help getting the return right.
Frequently asked questions
How much tax will I pay on £60,000 in 2026/27?
On a £60,000 salary in England, Wales or Northern Ireland for 2026/27, with no other income and the standard personal allowance, your income tax is £11,432. That's £37,700 taxed at 20% (£7,540) plus £9,730 taxed at 40% (£3,892). National Insurance is charged on top of that.
Is the income tax calculator accurate for self-employed people?
A general calculator gives a useful estimate, but the self-employed also pay Class 4 National Insurance on profits, at 6% between £12,570 and £50,270 and 2% above for 2026/27. Always check whether the tool includes National Insurance and any allowable expenses before trusting the figure.
Why is my personal allowance lower than £12,570?
If your adjusted net income is over £100,000, your personal allowance is reduced by £1 for every £2 above £100,000. It reaches zero at £125,140. That's why high earners can see an unusually high effective tax rate on income in that band.
Do calculators include National Insurance and student loans?
Some do, some don't. HMRC's estimator for employees includes National Insurance, pension and student loan deductions. A pure income tax calculator may show tax only. Check what's included so you don't under-budget for what actually leaves your account.
Does this apply if I live in Scotland?
No. Scotland sets its own income tax rates and bands, which differ from those in England, Wales and Northern Ireland. The figures in this guide are for the rest of the UK. If you're a Scottish taxpayer, use a calculator set to Scottish rates.
