Last updated: 14 October 2026
How do you know how much tax you owe?
The quickest way is to sign in to your HMRC personal tax account or the HMRC app. It shows your tax code, your estimated income tax for the current year, any underpayment or refund from earlier years, and your Self Assessment balance if you file returns. If you’re employed only, your payslips and P60 show the tax deducted, and HMRC sends a P800 or Simple Assessment if you’ve paid too much or too little. If you file Self Assessment, the tax calculation (SA302) shows exactly what you owe for the year.
Where to check
| Your situation | Where to look |
| Employed or pensioner | Personal tax account, P60, P800 letter |
| Self-employed or landlord | Self Assessment online account, SA302 calculation, statement |
| Simple Assessment (e.g. State Pension over allowance) | PA302 letter |
| Company director | Personal tax account and Self Assessment |
| Company’s corporation tax | Business tax account, CT600 calculation |
Working it out yourself for 2026/27
| Band (England, Wales, NI) | Taxable income | Rate |
| Personal Allowance | Up to £12,570 | 0% |
| Basic rate | £12,571 to £50,270 | 20% |
| Higher rate | £50,271 to £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
Dividends are taxed at 10.75%, 35.75% and 39.35% in 2026/27 after the £500 dividend allowance. Scottish taxpayers have different rates on earned income.
Example
Kevin is self-employed with £42,000 profit in 2026/27. His income tax is (£42,000 − £12,570) × 20% = £5,886. Class 4 NIC is 6% on profits above £12,570, so £1,765.80. His total bill is £7,651.80. As this is over £1,000, he’ll also make payments on account of £3,825.90 each towards 2027/28.
Checking your tax code
Your tax code tells your employer how much tax-free pay you get. 1257L is the standard code. If you have benefits or untaxed income, it will be lower. A wrong code can mean you owe tax at the year end, so check it each April.
If you think HMRC is wrong
- Check the figures against your P60 and records
- Contact HMRC within 60 days of a P800 or Simple Assessment if you disagree
- Ask for a review of a Self Assessment calculation or amend your return within 12 months of the filing deadline
Common mistakes
- Ignoring a P800 because you think PAYE covered everything
- Forgetting payments on account in your Self Assessment budget
- Not checking your tax code after a job change
- Using English rates if you’re a Scottish taxpayer
Tax on other income
Savings interest over your Personal Savings Allowance, rental profits and capital gains all add to your bill. Rental profit is taxed at your normal income tax rates, while gains on residential property are taxed at 18% or 24% after the £3,000 annual exempt amount. If you have several sources of income, a Self Assessment calculation is the most reliable way to see the full figure.
Frequently asked questions
When do I pay tax owed?
Self Assessment by 31 January; P800 underpayments are usually coded out.
Can I see previous years?
Yes, in your personal tax account.
Is there a tax calculator?
HMRC has estimators online.
What if I can’t pay?
Ask for a Time to Pay arrangement.
Related: whether you need a tax return, Scottish income tax rates and negative tax codes.
Talk to Accotax
Want this handled for you? Our team at Accotax can help with tax calculations and returns. See our Self Assessment tax return service service, or contact us for a free, no-obligation quote.
This page is general guidance based on HMRC rules for the 2026/27 tax year, checked against gov.uk on 14 October 2026. It is not personal advice, so speak to an accountant about your own situation.
