How to use the tax code calculator
- 1 Find your tax code on your payslip, P60, P45 or in your HMRC online account.
- 2 Enter the number part, for example 1257 in 1257L.
- 3 Choose the letter or code type, such as L, M, K, BR or 0T.
- 4 Optionally enter your yearly pay from that job to see the tax it should take.
Worked example
A code of 1257L on a salary of £35,000. You can earn £12,570 tax-free, about £1,047.50 a month. The remaining £22,430 is taxed at 20%, so the tax for the year is about £4,486, or roughly £373.83 a month. On a BR code the same pay would have £7,000 taken.
When your tax code is wrong
- Common causes: a new job without a P45, a second job, a company car or medical insurance, or HMRC estimating untaxed income.
- Emergency codes end in W1, M1 or X. They tax each payslip on its own, so you can pay too much until the right code arrives.
- K codes add to your taxable pay, but your employer cannot take more than half of your pay in tax in one period.
- Fixing it: update your details in your HMRC online account or the HMRC app. Overpaid tax is usually refunded through your next payslips.
Check the yearly tax you should pay with the Income Tax Calculator, and your full payslip with the Take-Home Pay Calculator.
Features
Plain English meaning
Every common suffix and special code explained, from L and M to D1 and NT.
Tax-free pay
The yearly and monthly amount you can earn before tax under the code.
K code handling
Shows the amount added to your taxable pay instead of an allowance.
Tax estimate
Expected income tax for the year on the pay you enter.
When to use it
New job checks
Make sure your first payslip uses the right code and not an emergency code. Check your yearly tax with the Income Tax Calculator.
Second jobs
Understand why a second job is taxed on BR or D0. See your payslip with the Take-Home Pay Calculator.
Company benefits
See how a company car or medical insurance reduces your allowance. Married? Try the Marriage Allowance Calculator.
Overpaid tax
Spot a wrong code early so you can ask HMRC to correct it. Bonus month? Use the Bonus Tax Calculator.
Related Tax tasks
Frequently asked questions
What does 1257L mean?
It is the standard tax code for 2026/27. The number 1257 means you can earn £12,570 tax-free in the year, and the letter L means you get the normal personal allowance with nothing else added or taken away.
How is the number worked out?
HMRC starts with your personal allowance, adds things that increase it, such as Marriage Allowance received or professional fees, takes away things that reduce it, such as taxable benefits or untaxed income, then drops the last digit.
What does a K code mean?
Your deductions are bigger than your allowance, so instead of tax-free pay an amount is added to your taxable pay. K codes often come from company benefits or tax owed from an earlier year. Tax under a K code cannot exceed half your pay in a period.
What are BR, D0 and D1 codes?
These codes give no tax-free pay. BR taxes all pay from that job at 20%, D0 at 40% and D1 at 45%. They are normally used for a second job or pension when your allowance is already used elsewhere.
What does 0T mean?
No personal allowance is given, so all your pay is taxed using the normal bands. It is common when HMRC has not got enough details, such as when you start a job without a P45.
What is an emergency tax code?
A code followed by W1, M1 or X, such as 1257L M1. Each pay period is worked out on its own instead of across the year, so you may pay too much until HMRC sends the correct code.
What do M and N mean?
M means you receive Marriage Allowance from your spouse or civil partner, giving you a higher allowance. N means you have transferred part of your allowance to your partner.
What does a T code mean?
T means there are other items HMRC needs to review in your code, or you have asked HMRC not to use a standard code. It is also used when your allowance is reduced because income is over £100,000.
What do S and C at the start mean?
S means you pay Scottish income tax rates and C means Welsh rates. Welsh rates are currently the same as in England, while Scottish bands differ.
What does NT mean?
No tax is taken from this income at all. It is rare and used in special cases, such as some non-resident workers.
How do I change a wrong tax code?
Check it in your personal tax account or the HMRC app, and update your details there or contact HMRC. Your employer cannot change the code without an instruction from HMRC.
Will I get a refund if my code was wrong?
Usually yes. Overpaid tax is often refunded through your pay once the code is corrected, or after the tax year ends. Underpaid tax may be collected through next year's code.
Results are estimates based on the official rates linked above. Confirm important figures with the issuing authority or a qualified adviser before you act on them.
Built and reviewed by Hamza Farooq, founder and lead developer
· Last updated
· How we check our tools
· Report a problem