UK Tax Codes Explained: Numbers, Letters and Emergency Codes

Your tax code is a string of numbers and letters that helps your employer or pension provider work out how much Income Tax to deduct. It reflects the allowances and adjustments HMRC has allocated to that source of income, so checking it against HMRC's record is an important part of understanding a payslip.

What does the tax code 1257L mean?

The standard tax code for many employees with one job in the 2026/27 tax year is 1257L, although your circumstances can produce a different valid code.

• 1257: You usually multiply the number by 10 to estimate the tax-free income allocated to that employment or pension: £12,570.
• L: This indicates entitlement to the standard tax-free Personal Allowance.

1257L usually gives £12,570 of tax-free allowance across the tax year, subject to how the code is operated. A Scottish taxpayer's code usually begins with S and Scottish rates apply to relevant income. Our Take-home Pay Calculator models common codes as annual estimates; it does not reproduce cumulative PAYE payroll records.

What is an emergency tax code or “emergency tax number”?

An emergency tax code ends in W1, M1, X or NONCUM. Examples include 1257L W1 for weekly pay and 1257L M1 for monthly pay. “Emergency tax number” is an informal search phrase; the item shown on a payslip is a tax code, not a separate HMRC number.

Instead of using your total income and tax so far in the year, an emergency code works from that week or month alone. This can produce too much or too little tax. It is often temporary after starting a job when the employer does not yet have the previous pay and tax details. Give a valid P45 to your new employer if you have one. HMRC says a new code can take up to 35 days after starting a job; if it still appears wrong after that, check and update your details online.

What do BR, D0 and D1 tax codes mean?

Your Personal Allowance may be allocated to one employment or pension rather than repeated across every PAYE source. HMRC commonly uses these codes for a second job or pension:

• BR: all income from this job or pension is taxed at the basic rate.
• D0: all income from this source is taxed at the higher rate.
• D1: all income from this source is taxed at the additional rate.

Remember that National Insurance is worked out separately on each job and ignores your tax code entirely, so a second job is still subject to NI in its own right.

Why might a code be 647L, 1288L or another number?

Not everyone should have 1257L. A code such as 647L or 1288L may reflect a different tax year or an individual adjustment for untaxed income, employment expenses, benefits or tax already owed. The number usually indicates the tax-free income allocated to that PAYE source after HMRC's adjustments, with the final digit removed. Do not assume an unfamiliar code is wrong: compare the code on your payslip with HMRC's current-year record and use the official checker to see its calculation.

What does a K tax code mean?

A tax code beginning with K means the income HMRC is collecting tax on through that source is greater than the available Personal Allowance. This can happen because of taxable benefits, State Pension or tax owed from an earlier year. K codes use a different calculation from ordinary numeric codes, so check HMRC's breakdown rather than treating the number as a tax-free allowance.

How to check and update a tax code

1. Compare the code on your payslip with the code in HMRC's current-year Income Tax service or app.
2. Check your employments, pensions, estimated income, benefits and expenses for missing or incorrect details.
3. Update the details online. HMRC describes this as the quickest way to correct a code.
4. After HMRC issues a new code, check that it reaches your employer and appears on a later payslip.