Why Has HMRC Put You on the 0T Tax Code?

What Does the 0T Tax Code Mean?

The 0T Tax Code means that no tax-free Personal Allowance is being applied to the income from that particular job or pension.

Under the standard 1257L tax code, most employees receive a tax-free Personal Allowance of £12,570 for the 2026/27 tax year. This means the first £12,570 of their annual taxable income is generally free from Income Tax, provided they are entitled to the full allowance.

With the 0T Tax Code, however, Income Tax is calculated from the first pound of taxable earnings. Your employer applies the relevant basic, higher and additional tax rates depending on the amount you earn.

This doesn’t necessarily mean you’ve lost your Personal Allowance entirely. It may already be allocated to another employment or pension, or HMRC may not yet have enough information to calculate your correct tax code.

Source: GOV.UK – What your tax code means

Why Has HMRC Put You on the 0T Tax Code?

Receiving a 0T Tax Code doesn’t always mean something has gone wrong. HMRC may apply it for several reasons, depending on your employment history, income and available Personal Allowance.

1. You’ve Started a New Job Without a P45

If you’ve recently started a new job without providing a P45, your employer may not have enough information about your previous earnings and tax deductions. A P45 helps them calculate the correct tax. Our guide to P45, P60 and P11D forms explains why these documents matter.

Without it, you may temporarily receive the 0T Tax Code, particularly if the information on your starter checklist is missing or incomplete.

2. You Have More Than One Job or Pension

If you have two jobs or receive both employment and pension income, your Personal Allowance may already be used against one source. 

For example, if your main job uses your full allowance, HMRC may apply the 0T Tax Code to your second job. This doesn’t necessarily mean you’re paying too much tax.

3. Your Personal Allowance Has Been Reduced to Zero

If your adjusted net income exceeds £100,000, your Personal Allowance reduces by £1 for every £2 earned above that threshold. Once your income reaches £125,140, the standard allowance is completely withdrawn. 

In this situation, HMRC may apply the 0T Tax Code because you’re no longer entitled to a tax-free Personal Allowance.

4. HMRC Doesn’t Have the Correct Information

Sometimes, HMRC may have outdated or incomplete information about your employment. For example, your previous job might still appear as active, or your new employer’s details may not have been updated. 

This could result in an incorrect tax code. If you’ve recently changed jobs, check that HMRC has your current employment and income details.

Sources: GOV.UK – Understanding employee tax codes

How Much Tax Will You Pay on the 0T Tax Code?

The 0T Tax Code can reduce your take-home pay if you would otherwise qualify for the full Personal Allowance.

For example, if you earn £3,000 per month (£36,000 annually), here’s how your monthly Income Tax could compare under the standard 1257L and 0T tax codes.

In this example, £209.50 more Income Tax is deducted each month under the 0T Tax Code. However, this doesn’t necessarily mean you’re overpaying, as your Personal Allowance may already be used elsewhere.

Want to see how your tax code affects your salary? Use our Take Home Pay Calculator to estimate your Income Tax deductions and take-home pay.

Note: This illustration uses 2026/27 Income Tax rates for England and Northern Ireland, assumes no other taxable income or adjustments, and excludes National Insurance and pension contributions. Actual PAYE deductions may vary.

Is the 0T Tax Code an Emergency Tax Code?

The 0T Tax Code can be used temporarily when an employer doesn’t have enough information about a new employee’s tax position. However, 0T on its own does not necessarily mean you’re on an emergency tax code.

You may also see 0T followed by W1, M1 or X on your payslip. These indicate that tax is being calculated on a non-cumulative basis, meaning your employer considers only the current pay period rather than your total earnings and tax deductions for the year.

For example, 0T M1 means no Personal Allowance is applied, and tax is calculated separately for that month. Once HMRC receives the necessary information, it may issue a revised tax code. However, if your Personal Allowance has genuinely been used up, the 0T code may remain appropriate.

If you’ve recently changed jobs or noticed W1, M1 or X on your payslip, our guide explains how an emergency tax code could mean you’re paying too much tax.

What’s the Difference Between the 0T and BR Tax Codes?

Both 0T and BR tax codes mean no Personal Allowance is applied to that particular job or pension. The main difference is how Income Tax is calculated.

For example, someone on the BR code generally pays 20% tax on that income, even if their overall earnings put them in a higher tax band. With 0T, higher rates can apply depending on earnings from that source.

The correct code depends on your overall income and how HMRC allocates your allowances. If you’re unsure about other codes on your payslip, our guide to understanding UK tax codes explains what they mean.

How to Fix the 0T Tax Code If It’s Wrong

If you believe your 0T Tax Code is incorrect, you can check it through your Personal Tax Account or the HMRC app and review your employment details, estimated income and tax allowances.

To correct your tax code:

1. Check your payslip and tax code notice. Confirm whether your code is 0T, 0T W1 or 0T M1.
2. Review your employment records. Make sure HMRC has accurate information about your current and previous jobs.
3. Provide your P45 if necessary. If you’ve recently changed jobs, give your new employer your P45 or ensure you’ve completed the starter checklist correctly.
4. Update HMRC. Use the online Income Tax service to correct missing or inaccurate information.
5. Check your next payslip. Once HMRC issues an updated code, confirm that your employer has applied it.

HMRC generally updates the tax code within 15 working days where a change is needed. If you’ve recently started a new job, allow up to 35 days for HMRC to receive your employment details before contacting them about your tax code.

Sources: GOV.UK – If you think your tax code is wrong

Can You Get a Tax Refund If You’ve Been on the Wrong 0T Tax Code?

Yes. If the 0T Tax Code resulted in you paying more Income Tax than you owed, you may be entitled to a refund.

Once HMRC receives the correct employment and income information, it can recalculate your tax position and issue an updated tax code where necessary.

If the correction takes place during the tax year, overpaid tax may be refunded through your wages when your employer applies the revised code. In other cases, HMRC may review your tax position after the tax year ends and arrange a repayment.

The key point is that receiving a 0T Tax Code does not automatically qualify you for a refund. HMRC must first establish whether the amount of Income Tax deducted was greater than your actual liability.

Source: GOV.UK – If you’ve paid too much or too little tax

Should You Be Concerned About Your 0T Tax Code?

Seeing the 0T Tax Code on your payslip doesn’t necessarily mean HMRC has made a mistake, but it shouldn’t be ignored either.

If you’ve recently changed jobs, started receiving pension income or noticed an unexpected reduction in your take-home pay, checking your tax code could help you understand whether the deductions are correct.

And if you’re unsure why HMRC has applied the code, feel free to contact us for professional advice. We can help you review your tax position, identify potential overpayments and understand whether any further action is needed.