UK tax code checker 2026/27. Free, private

Is your tax code right, and are you overpaying?

Type the code from your payslip, add the pay and tax shown year-to-date, and see what the code means, what tax it should have produced, and whether you have paid more than the standard code would take. A second section works out what your code should be.

Written from the published rules without a live lookup. Rates and rules change; GOV.UK and HMRC decide. Not tax advice.

1. Check my payslip against my code

Tax code (e.g. 1257L, BR, K475, S1257L, 1257L M1)

Paid

Pay period number this tax year (month 1 = April)

Taxable pay so far this tax year (£)

Tax paid so far this tax year (£)

Enter the details, then click Check my code.

Result

Item	To date

2. What should my code be?

Where you live for tax

Estimated taxable income this year (£)

Taxable benefits (£ a year)

Other income not taxed at source (£)

Underpaid tax to collect (£)

Rate it is collected at (%)

Marriage Allowance

Enter the details, then click Work out my code.

What it does, and what it leaves to you

Covers: L, M, N, T and K codes, BR, D0, D1, 0T and NT, Scottish S and Welsh C prefixes, week 1/month 1 (emergency) basis, cumulative tax to date, the 2026/27 England/Wales/NI and Scottish bands, and the £100,000 allowance taper.
Gives: the meaning of the code, tax expected on your code and on the standard code, the likely overpayment and what to do about it, and a text file for your records.
Not decided: second jobs, taxable benefits worked out for you, pension relief, Gift Aid, tax paid in a previous job this year, NI and student loans, and HMRC's exact table rounding. HMRC or an adviser decides these.

Common questions

What does tax code 1257L mean?

1257L is the standard code for most people in 2026/27. The number times 10 (plus 9) is your tax-free pay for the year, about £12,579 from the £12,570 Personal Allowance, and the L means a standard allowance.

Why am I on tax code BR, 0T or W1/M1?

BR taxes all pay at 20% and 0T gives no allowance; they are common on a new job when your employer has no P45 yet. W1, M1 or X mean emergency tax, where each pay period is taxed alone. Giving your employer your P45 or updating HMRC usually corrects it, and the overpaid tax comes back through your pay.

How do I get a tax refund if I paid too much?

If your code is corrected during the year, payroll refunds the difference in your pay. If you are still overtaxed after the year ends, HMRC normally sends a P800 or you can claim online. Check your tax code and personal tax account on GOV.UK.

What does a K code mean?

A K code means HMRC has added more taxable income or benefits to your pay than your allowance covers, so a set amount is added to your pay before tax is worked out. It can be right, for example for a company car, so check what it is made of.

Is my data uploaded anywhere?

No. Everything is calculated in your browser and nothing is sent.