# Tax code checker: what do 1257L, M1 and BR mean? URL: https://computenow.co.uk/tax-code-checker/ > Did your payslip shrink? Check what your tax code means, from 1257L to emergency codes like M1 and W1, and what it does to your take-home pay. This calculator shows a worked example below. To use your own figures, add them to the URL as query parameters (listed in https://computenow.co.uk/llms.txt), for example https://computenow.co.uk/tax-code-checker/?=. [What's Left, step 1 of 7: What will I take home?](https://computenow.co.uk/money-plan/#steps) # Tax code checker Type in the tax code from your payslip to see what each part means and how much you take home with it. 2026/27 tax yearUKRates checked 18 October 2026 By the ComputeNow team, checked against GOV.UK and HMRC[Sources (3)](#sources)[How we calculate](https://computenow.co.uk/methodology/) With tax code 1100L you take home £2,367.13 a month: £26.17 less than with the standard code 1257L. ## Your tax code explained 1100L against 1257L | Item | 1100L | 1257L | | --- | --- | --- | | Tax-free pay for the year | £11,000.00 | £12,570.00 | | Income Tax a year | £4,800.00 | £4,486.00 | | National Insurance a year | £1,794.40 | £1,794.40 | | Take-home a month | £2,367.13 | £2,393.30 | 1100: 1100 × 10 = £11,000 of tax-free pay for the year. That is £1,570 less than the standard £12,570, usually because HMRC is collecting tax on a company benefit, untaxed income or tax you owe from an earlier year. L: You get the standard tax-free Personal Allowance, adjusted by the number if HMRC knows about other income or reliefs. If this code is wrong, you may have paid too much tax. If so, HMRC will pay it back, and you don't need a company to claim it for you. Check your tax code in the HMRC app or on GOV.UK. If your hours or pay rate look wrong, ask your employer's payroll team. If your tax code looks wrong, HMRC sets it: check it in the HMRC app or on GOV.UK. Have your latest payslip and your P45 or P60 to hand. This is an estimate. Your payslip can be a little different because of how your employer rounds figures or when deductions are taken. We've assumed 2026/27 rates for England, Wales and Northern Ireland, tax code 1100L, no pension and no student loan; change these under More options. If you think your code is wrong, check it with HMRC: a wrong code is corrected through your pay, or you get a refund or a bill after the tax year ends. [With tax code 1100L you take home £2,367.13 Breakdown](#result) ## Why your payslip might differ Your payslip can be different from this if: - your tax code isn't 1257L (check the code on your payslip); - you pay into a pension or repay a student loan (add them under More options); - you started or changed job this tax year, and you're on an emergency code; - this month included a bonus or overtime; - you have more than one job; - you live in Scotland, where the tax rates are different. For hours or pay, ask your payroll team. For a tax code, ask HMRC. [Why is my pay different this month?](https://computenow.co.uk/guides/why-is-my-pay-different-this-month/) ## How a tax code works A tax code tells your employer how much of your pay to leave untaxed. For most codes, multiply the number by 10 to get your tax-free pay for the year: 1257L means £12,570, the standard Personal Allowance. On £35,000, the code 1100L gives you £11,000 of tax-free pay instead of £12,570. The extra £1,570 is taxed at 20%, so you take home £2,367.13 a month instead of £2,393.30. A lower number like this usually means HMRC is collecting tax on a company benefit, untaxed income or an underpayment from an earlier year. The letter says why: L is the standard allowance, M and N are Marriage Allowance, T means other adjustments, and K means you owe tax on more than your allowance. Codes without a number, like BR, D0 and 0T, tax all your pay. An S at the start means Scottish rates; W1, M1 or X at the end means an emergency code. Read [tax codes explained](https://computenow.co.uk/guides/tax-codes-explained/) for every code, with examples. ## Common questions ### Why am I on emergency tax? An emergency tax code (such as 1257L W1, 1257L M1, 1257L X or 0T) is a temporary code used when HMRC does not yet have your details, often when you start a new job without a P45. It is common, and usually put right once HMRC has your details. Any extra tax taken is normally paid back through your wages, or you can claim it. ### How do I check if I am on the right tax code? Compare the code on your payslip with what you expect. Most people with one job should have 1257L, or S1257L in Scotland, which gives £12,570 of tax-free pay. The HMRC app and your personal tax account on GOV.UK show your code and why it is what it is. If it is wrong, HMRC corrects it, and any tax you overpaid is paid back. You don't need a company to claim it for you. ## Related calculators [Take-home pay calculator Your pay after Income Tax and NI](https://computenow.co.uk/take-home-pay/)[Two jobs tax calculator How a second job is taxed](https://computenow.co.uk/two-jobs-tax-calculator/)[Income Tax calculator Your tax band by band](https://computenow.co.uk/income-tax-calculator/) ## Guides and help ### Our guides [What does my tax code mean? 1257L, BR, 0T and K explained Read your code and see what it does to your pay](https://computenow.co.uk/guides/tax-codes-explained/)[How Income Tax bands work in 2026/27 Personal Allowance, basic, higher and additional rate](https://computenow.co.uk/guides/income-tax-bands-2026-27/) ### Official services and free advice [Check your Income Tax for this year GOV.UK: your tax code and pay so far](https://www.gov.uk/check-income-tax-current-year)[Tax codes explained GOV.UK: what yours means, and fixing a wrong one](https://www.gov.uk/tax-codes)[Understanding your payslip GOV.UK: deductions and your rights](https://www.gov.uk/understanding-your-pay) ## Sources Each source was last checked on 18 October 2026. - [GOV.UK: Rates and thresholds for employers 2026 to 2027](https://www.gov.uk/guidance/rates-and-thresholds-for-employers-2026-to-2027) - [GOV.UK: Income Tax rates and Personal Allowances](https://www.gov.uk/income-tax-rates) - [GOV.UK: Scottish Income Tax](https://www.gov.uk/scottish-income-tax) These results are an estimate, not financial advice. They use the 2026/27 rates in force on 24 October 2026 and the inputs shown, so your actual tax, pay or costs may differ. Before making a decision about your money, check the figures with HMRC or your provider, or speak to a regulated financial adviser. Free, impartial guidance is available from MoneyHelper. This page explains the rules using the 2026/27 rates in force on 24 October 2026. It is general information, not financial advice. For decisions about your own money, speak to a regulated financial adviser, or get free, impartial guidance from MoneyHelper.