// Source citations for the factual claims in this guide (kept out of the // rendered tree: flow-level MDX comments break Next scroll-on-navigation). export const sources = [ "P800 tax calculation letters are sent between June and March of the following tax year, to employed people and pensioners (not Self Assessment filers); common triggers include wrong tax codes and overlapping employments: https://www.gov.uk/tax-overpayments-and-underpayments, retrieved 2026-06-12.", "P800 refund routes and timescales, verified 2026-06-12 at https://www.gov.uk/tax-overpayments-and-underpayments/if-youre-due-a-refund: claim online by bank transfer using the P800 reference and NI number and 'You'll be sent the money within 5 working days if you've claimed online'; if the letter says a cheque is coming, 'You do not need to contact HMRC to make a claim' and 'You'll get your cheque within 14 days of the date on your letter'. Claims can also be made via the personal tax account or HMRC app.", "Proactive claims without a P800 go through the free gov.uk tool covering pay from a job, job expenses, pension income, redundancy and savings interest, among others: https://www.gov.uk/claim-tax-refund, retrieved 2026-06-12.", "Four-year claim window: 'The person must make the overpayment relief claim within four years of the end of the relevant tax year or accounting period', HMRC Self Assessment Claims Manual SACM12005, https://www.gov.uk/hmrc-internal-manuals/self-assessment-claims-manual/sacm12005, retrieved 2026-06-12.", "2026/27 personal allowance of £12,570 (about £1,047 per month under cumulative PAYE) from site/lib/tax/config.ts; emergency code 1257L W1/M1/X behaviour (each payday taxed in isolation, earlier overpayments not refunded through payroll until the code goes cumulative) from site/lib/tax-code-checker.ts.", ];

Guide · 5 minute read · Updated 2 Jul 2026

Am I due a tax refund from HMRC?

Quite possibly, if you changed jobs, sat on an emergency tax code, took a pay cut mid-year, or juggled more than one job. HMRC reconciles PAYE after each tax year and posts P800 letters between June and March. Claiming is free and takes minutes.

Why PAYE overpays in the first place

PAYE is a forecasting system. Each payday, your employer's software assumes this year's income will carry on at the current rate, spreads your tax-free personal allowance (£12,570 in 2026/27, roughly £1,047 a month) evenly across the year, and deducts tax accordingly. When real life matches the forecast, the tax comes out right. When it does not, the system drifts, and most of the drift situations leave you overpaid rather than underpaid.

The good news is that cumulative PAYE self-corrects within the tax year: if your code is right and you stay in the same job, an early overpayment flows back through later payslips automatically. Refund situations arise when something breaks that self-correction: a wrong code, a job gap, or earnings that stop before the year does.

The situations that usually trigger a refund

You changed jobs, with a gap between them. Your allowance kept accruing during the weeks you were not paid, but nobody was applying it. If your new employer got your P45 promptly, the first cumulative payslip refunds the difference. If the tax year ended while you were still out of work, the overpayment sits with HMRC until reconciliation.

You were put on an emergency code. Codes ending W1, M1 or X tax each payday in isolation, so earlier overpaid months are not refunded through payroll until you move back to a cumulative code. This is its own rabbit hole; our emergency tax guide covers the X, W1 and M1 codes and both routes to getting that money back.

Your pay dropped mid-year, or you stopped working. If you earned well in spring and little after autumn, the early months were taxed on the assumption the high pay would continue. Stop work entirely partway through the year and the unused allowance for the remaining months is an overpayment with no payroll left to repay it through.

You had more than one job. A second job is typically taxed at basic rate from the first pound (code BR), which is correct only if your main job uses your whole allowance. If your combined income is modest, or your main job did not use the full allowance, the second job was overtaxed. Run your code through the tax code checker to see whether the split makes sense, and use the take-home pay calculator to sanity-check what your total deductions should look like.

Other common triggers include a first flexible pension withdrawal (taxed on an emergency basis), work expenses you never claimed, and untaxed-interest estimates baked into your code that turned out too high.

The P800 cycle: June to March

After the tax year ends on 5 April, HMRC reconciles what you paid against what you owed. If the numbers do not match, it sends a P800 tax calculation letter; these go out between June and March of the following tax year. P800s go to employed people and pensioners. If you file Self Assessment, your refund or bill comes through your return instead, so you will not get one.

Earlier letters tend to go to simpler cases, so do not panic if a friend gets theirs in July and yours arrives in autumn. And the absence of a letter does not mean the absence of a refund: HMRC can only reconcile from the data it holds, so if you think you have overpaid, you can claim proactively through the free check-a-refund tool on gov.uk rather than waiting.

How to claim, and how long it takes

If your P800 says you are owed money, the fastest route is claiming online (through gov.uk, your personal tax account, or the HMRC app) using the reference number on the letter and your National Insurance number. Claimed online, the bank transfer arrives within 5 working days. If the letter says a cheque is coming, you do not need to do anything; it arrives within 14 days of the date on the letter.

You can also claim for past years: HMRC's time limit is four years from the end of the tax year the overpayment relates to. In June 2026 that means tax years back to 2022/23 are still claimable.

You never need a fee-charging refund agent

Search "tax refund" and you will hit a wall of companies offering to claim your money for a cut of it, sometimes alongside admin fees, and often via an assignment that routes future refunds to them too. Everything they do, you can do yourself on gov.uk for free, usually in under ten minutes, because HMRC has already calculated the number; the agent adds no expertise, only an invoice. The same applies to expense claims and pension overpayments. If a letter or ad implies HMRC requires an agent, it does not.

The only genuine reason to pay anyone is complexity, such as multi-year foreign income or residence questions, and then you want a qualified accountant, not a refund factory.

Common questions

How do I know if HMRC owes me money?

Wait for a P800 tax calculation letter, sent between June and March after the tax year ends, or check proactively in your personal tax account or the HMRC app. Common signs you have overpaid: a job change with a gap, an emergency tax code (W1, M1 or X), a mid-year pay drop, or a second job taxed at basic rate when your allowance was not fully used.

What is a P800 letter from HMRC?

It is HMRC's end-of-year tax calculation for employed people and pensioners, comparing the tax you paid through PAYE against what you actually owed. It tells you whether you overpaid, underpaid, or paid the right amount, and how any refund will be paid. Self Assessment filers do not get one; their return does the same job.

How long does a tax refund take from HMRC?

If your P800 says you are due a refund and you claim online by bank transfer, HMRC says the money is sent within 5 working days. If the letter says you will get a cheque, it arrives automatically within 14 days of the date on the letter, with no claim needed.

Can I claim a tax refund from previous years?

Yes. The time limit is four years from the end of the tax year the overpayment relates to, so in 2026/27 you can still claim for tax years back to 2022/23. Claims for earlier years than that are out of time.

Are tax refund companies worth it?

Almost never. They take a percentage of your refund, sometimes plus fees, for doing something gov.uk lets you do free in minutes. HMRC has usually already calculated the amount. Paid help only makes sense for genuinely complex affairs, and then from a qualified accountant rather than a volume refund agent.

Guidance and education, not regulated financial advice.