What is emergency tax and can I claim a refund?

There are multiple reasons why you might find yourself on an emergency tax code, paying more tax than necessary.

Read on to find out when and why this happens, plus how to get your money back.

What is emergency tax, and how does it work?

You usually get put on an emergency tax code because your employer (or pension provider) does not have your  correct tax code so you end up paying an estimated amount.

Rather than factoring the tax you have paid so far in the current tax year, emergency tax codes are ‘non cumulative’ and will assume you are paid that amount every week or month and tax it accordingly.

This means that most people will pay more tax than necessary (additional rate taxpayers may underpay).

It’s important to understand that this is a temporary measure - once an up to date tax code is received, you should be taxed accurately and any overpayments can be refunded. 

If your tax code on your payslip contains ‘W1’, ‘M1’, or ‘X,’ that means you’re on an emergency tax rate. 

Learn more: what is tax code 1257L and what does it mean?

Why am I on emergency tax?

You might find you have been placed on emergency tax for several reasons.

These include: 

• You have started a new job, and HMRC did not receive your income details in time

• Your employer accidentally used the wrong tax code

• You have started a new job after a period of self-employment

• You have more than one job at a time

• You’re a student and working during the holidays

• You’re moving from a full-time to part-time job

• You’re starting to take company benefits or the state pension

When might you get an emergency tax code on pension withdrawals?

You may also pay emergency tax on your pension income.

This can happen when you make your first, flexible lump sum withdrawal from a defined contribution pension because your pension provider does not have an up to date tax code for you.

In the majority of cases this means you end up paying more tax than you owe.

What is a P800?

A P800 is an end-of-year tax calculation letter that HMRC will send you if you have overpaid or underpaid on your tax.  

The letter will tell you if you need to pay more or whether you’re eligible for a tax refund.

There will also be a more detailed breakdown of the calculation.  

You don’t usually need to contact HMRC when you receive a P800 unless you believe there is a mistake in the figures. 

How can you claim back emergency tax?

You can get back overpayments caused by an emergency tax code in various ways.  

Firstly, if your P800 shows you’re due a refund, HMRC should tell you how they will repay you in the letter. Note, that since 2024, repayments are no longer being paid automatically.

Instead you will need to submit a claim for your refund, which can usually be paid via an online bank transfer. Or, you can request a cheque.

It’s also important to ensure the HMRC calculations match your records in case the payment is wrong.

If they send you an overpayment and you fail to declare it, they could charge you a penalty, plus you would have to send the extra money back. 

If you think you have overpaid tax in the current 2025/26 tax year, but this has not been communicated through a P800 notice, it’s likely there’s an issue with your tax code.  

To claim the tax back, you should inform HMRC before the end of the tax year, either online using your personal tax account or by telephone.

You can find the HMRC number on GOV.UK. 

Before you get in touch, make sure you have all the essential details to hand, such as: 

• Your name, address, date of birth and National Insurance number.

• Your employers and/or pension providers.

• Estimates of your earnings or pension income from each source during the tax year.

When claiming your HMRC emergency tax refund for a tax year that has already passed, it’s probably best to write to HMRC.

Be sure to mark your letter ‘repayment claim’ and use the address on GOV.UK.  

Your letter should include the full personal details mentioned above and copies of your P60s and P45s if you have them.

Clearly state why you are owed a repayment and how you would like to be paid.

Claiming back emergency tax paid on pensions

If you have paid emergency tax on a pension payment, you can speed up your refund by completing a form and submitting it to HMRC.

Which form you use, depends on your circumstances.

If you fully encashed your pension:

• Complete form P50Z if you have no other income in that tax year

• Complete form P53Z if you have other sources of income in that tax year

If you only partially encashed your pension:

• Complete form P55 if you don’t plan to make further withdrawals from the pension.

(If you do plan to make further withdrawals from your pension, you will get a new up to date tax code from HMRC).

How long does it take to get emergency tax back?

If HMRC accepts your claim, it can take between five days and eight weeks to receive repayment.

The exact timing depends on whether you are reclaiming earnings from work or a pension, how you applied and whether any security checks were necessary. 

How to avoid emergency tax

In some cases, you won’t be able to avoid being put on an emergency tax code. 

However, as a starting point, you should always ensure any new employer gets a copy of your P45. This will show them your earnings and the amount of tax that you have paid.

It may also help you avoid paying emergency tax if you can provide your pension provider with a current P45, before you make your first withdrawal.

Alternatively, you may be able to reduce the amount of emergency tax that you pay, by making a notional withdrawal first, before taking out a bigger lump sum. 

Seek professional advice

Emergency tax can be a frustrating and costly experience, but understanding how it works, and how to claim back overpaid tax, can help you stay in control.

That said, tax rules can be complex, especially if you have multiple income sources or changing financial circumstances.

Professional financial or tax advice can make all the difference, helping you avoid costly errors, claim what you're owed, and keep your finances on track.

Connect with an accountant or financial adviser with Unbiased today.