P800 refund: how to reclaim tax you're owed

Your employer gives HM Revenue & Customs (HMRC) details of how much income you receive, how much tax you have paid and the value of benefits you may have received during the tax year. 

After the end of each tax year, at some point between June and October of the new tax year, HMRC carries out an automatic check using this information to see if you have paid the right amount of tax.

If HMRC doesn't think you have paid the right amount of tax, it will send you a P800 tax calculation.

This will show you what tax HMRC thinks you should have paid. 

HMRC will never send these notifications by email, so watch out for these HMRC tax refund scams.

You should receive a P800 notification through the post.

Check your P800 tax calculation carefully, as HMRC may have inaccurate information, or may not have the full information to correctly calculate your tax. 

If you are due a repayment your P800 should tell you whether you can claim your refund online using a Gateway Account or whether HMRC will send you a cheque in the post.

Those that claim money back through their online can get a refund within five working days

If you are eligible to claim online but don’t do so within 45 days you’ll get a cheque sent to you, in about 60 days.

However, if HMRC thinks you haven't paid enough tax, it will write to you explaining they will collect underpaid tax through your tax code or telling you how to repay. 

If you have tax deducted from your earnings, or pension, through the PAYE (pay as you earn) system, you should receive a P60 from your employer, or pension company, every year.

This document outlines your income and deductions for the tax year just ended.

If you have more than one source of employment, you should get a P60 from each employer. The same goes for people who have more than one pension.

You should always check your P60s thoroughly to make sure your tax code, and any tax that has been deducted, is correct.

You can learn more about how tax codes work here.

If your employer or pension company hasn’t been informed of your tax code by HMRC, they may have put you on what’s known as an emergency code, which could mean paying more tax than you need to.

There are several reasons why an emergency code might apply.

• You have started a new job but didn’t get a P45 from your previous employer.
• You have started your first job after the beginning of the tax year, and you haven't received any taxable state benefits, State Pension or a company pension.
• You have started a new job but you have had another job(s) or received taxable state benefits during the year.
• Your tax code has changed during the year. This could happen if you started to receive company pension benefits or claim the State Pension, for example.
• You have started a new job but you were previously self-employed.

An emergency code usually ensures you receive the basic personal allowance and therefore means you will earn some of your income tax-free.

But it doesn’t make any provision for other reliefs or allowances you may qualify for.

You’re on an emergency tax code if your payslip says your tax code is one of the following:

• 1257L W1
• 1257L M1
• 1257L X

The W1 (week 1) or M1 (month 1) section of the code indicates that each week or month is being dealt with separately to give you an equal amount of net pay each time you receive your salary.

But this doesn’t take account of any tax you might have paid earlier in the tax year, which could mean you’re paying too much.

If you think you’re paying emergency tax, check with your tax office and ask them to send you and your employer the correct tax coding.

This will enable the right amount of tax to be deducted from your salary going forward. This will also give you the chance to claim any overpaid tax from HMRC.

If you have overpaid tax during your employment and the end of the tax year in which you overpaid has passed, you can make a claim for a refund.

Unless you pay your tax bill via Self Assessment, there isn’t a specific form you can use to claim a refund if you think you have paid too much tax on your earnings or pension income.

If you’re employed the way you claim a refund depends on the tax year you paid too much.

If you notice you are paying too much tax in the current tax year, your tax code might be wrong and you will need to tell HMRC.

Once corrected your refund will be adjusted through your pay.

If the error occurred during 2022/23, you will need to wait for the P800 tax calculation and the P800 will explain how to get a refund.

If your issue occurred from 2019/20 onwards, you make a claim online or write to HMRC explaining why you think you have overpaid.

When contacting HMRC in writing, it’s a good idea to mark your letter with ‘Repayment Claim’ so it can be prioritised.

Your claim should include the following information:

• Your personal details including your name, address, national insurance number and your PAYE reference shown on your pay slips.
• A rundown of your employment history including each of your PAYE reference numbers for different employers (if applicable), the dates when you were employed, your earnings, and the total amount of tax deducted.
• Explain why you think you’re entitled to a refund.
• Enclose copies of your P60s and P45s.
• Provide your bank details. If your refund can be transferred to your bank account it may speed the process up.
• Don’t forget to sign and date your letter.
• Keep a copy of your letter and arrange for proof of posting from the Post Office.

In theory, your claim should be resolved within five weeks, but delays can occur particularly if security checks are required before a repayment can be granted. Be prepared to chase HMRC up if necessary.

Keep a log of any calls you make to them including the date and time you called and the name of the person you spoke to, plus a summary of the conversation along with any advice you were given by the tax officer.

This may come in handy if there’s a dispute over your claim further down the line.

If you've made a mistake on your Self Assessment tax return and overpaid you've normally got 12 months from 31 January after the end of the tax year to correct it.

This is known as an 'amendment'. For example, you have until 31 January 2024 to make an amendment for your 2021/22 tax return.

You can only amend your return after this date if you received your return late (after 31 October). In this case, you must correct any mistakes within 12 months of the deadline for sending your return back.

If you sent your tax return on paper, you don't need to send in the whole tax return again.

Just write to HMRC and attach the pages that you want to change, clearly marked 'amendment'. You'll find the address on your tax return, your tax calculation or your Self-Assessment Statement.

If you sent your tax return online you can make the amendment online.

There's more information on claiming a self-assessment refund on the HMRC website.

Finally, you should know that the time limit for reclaiming overpaid tax has been cut back to four years. So, make sure you don’t miss the opportunity to get your tax back.