Is my tax code right?
The number in your code is your tax-free pay without its last digit: 1257L means £12,570. Tell us your code and what's going on, and we'll show whether it's the one we'd expect.
Your answer
Enter your tax code and your pay to check your code.
About this calculator
For anyone paid through payroll or a pension who wants to know what their tax code means, or thinks it's wrong.
Works with every code: L, M, N, T, K, 0T, BR, D codes and NT, with S for Scotland, C for Wales and emergency codes.
What happens to your answers
We don’t keep them. Your answers go to our server to do the sums and aren’t stored or logged. If you copy a link to your answers, they’re in the link itself, so only share it with people you trust.
How it’s worked out
The number in your code is your tax-free pay with the last digit dropped, so 1257L means £12,570. Payroll adds £9 back (£12,579), so you never lose out from the dropped digit.
We work out the code we'd expect: the £12,570 tax-free allowance (less any lost over £100,000), plus or minus £1,260 Marriage Allowance, less perks and other untaxed income, less tax owed from an earlier year divided by your rate of tax. If that comes out below zero you get a K code, which adds to your pay before tax, but it can't take more than half your pay.
Then we work out a year's tax on your pay at your code and at the code we'd expect. The difference is roughly what you'd overpay or underpay.
Worked example
Your tax code 1257L doesn't match the 857L we'd expect, so you could underpay about £800 of tax this year.
2026/27 tax year · England · £45,000 from this job, all year · same code all year · perks not taxed through payroll
| Your pay from this job a year | £45,000 |
|---|---|
| Your code 1257L: you get the standard tax-free allowance, less anything HMRC is collecting through your code | |
| 1257 × £10 = £12,570 tax-free. Payroll adds £9 (£12,579) because the last digit was dropped | £12,579 |
| Standard tax-free allowance | £12,570 |
| Taxable value of your perks | − £4,000 |
| Tax-free amount we'd expect from this job | £8,570 |
| The code we'd expect: 857L (£8,570 tax-free) | |
| Tax on your pay for the year at your code 1257L | £6,484 |
| Tax on your pay for the year at 857L | £7,284 |
| You'd underpay over the tax year | £800 |
Worked out using HMRC's published rates for the 2026/27 tax year (6 April 2026 to 5 April 2027), on a yearly basis.
Questions people ask
What does 1257L mean?
It's the usual code for 2026/27. You get £12,570 of tax-free pay from this job, the standard tax-free allowance (Personal Allowance). The L means you get the standard allowance.
My code is wrong. What should I do?
Check how HMRC worked it out in the HMRC app or your personal tax account, and update anything wrong there (Check your Income Tax). If you can't, contact HMRC. They'll tell you and your employer the new code within 15 working days, and payroll usually puts any overpaid tax right through your pay.
Why do I have an emergency code?
Usually because you've started a new job and your employer doesn't have your P45 yet. Give them your P45 if you have one. HMRC normally sends the right code within 35 days, and any tax overpaid in the meantime comes back through your pay.
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