You cannot carry forward your personal tax allowance in the UK. The £12,570 Personal Allowance is an annual entitlement under Section 35 of the Income Tax Act 2007, and any portion you don’t use by 5 April is lost.1Legislation.gov.uk. Income Tax Act 2007, Section 35 The one partial workaround is Marriage Allowance, which lets a non-taxpaying spouse or civil partner transfer £1,260 of their allowance to the other within the same tax year.
Why the Allowance Resets Every Year
The UK tax year runs from 6 April to the following 5 April, and the Personal Allowance is granted “for a tax year.” Each cycle is self-contained. If you earn £8,000 in a year, the remaining £4,570 of allowance simply expires; it doesn’t accumulate to make next year’s tax-free amount larger.
The same £12,570 applies whether you worked twelve months or twelve days.2GOV.UK. Income Tax Rates and Personal Allowances That’s why the question comes up so often: people starting a job mid-year, taking unpaid leave, or having a low-earning year assume the unused months must go somewhere. They don’t.
At the other end, higher earners lose allowance before they get a chance to leave any of it unused. Your Personal Allowance drops by £1 for every £2 of adjusted net income above £100,000, hitting zero at £125,140.2GOV.UK. Income Tax Rates and Personal Allowances
The Allowance Is Frozen Until April 2031
The £12,570 threshold has been held at that level since 2021/22 and is legislated to stay there through 5 April 2031.3GOV.UK. Income Tax: Maintaining the Personal Allowance and the Basic Rate Limit Until 5 April 2031 Every tax year from 2025/26 through 2030/31 uses the same figure. Because you can’t bank allowance from a low-earning year to soften a higher-earning one, the freeze means the tax-free portion of your income effectively shrinks in real terms without any change on paper.
Marriage Allowance: The Only Route to Salvage Unused Allowance
If your income is below £12,570 and you have a spouse or civil partner who pays income tax at the basic rate, you can transfer 10% of your Personal Allowance — a fixed £1,260 — to them. That cuts their tax bill by up to £252 a year.4GOV.UK. Marriage Allowance
This isn’t a true carry forward and it isn’t flexible. You transfer £1,260 or nothing; you can’t scale it to match how much allowance you actually left unused. Anything above that £1,260 still expires at year-end.
Who Qualifies
The lower-earning partner must be married or in a civil partnership and either pay no income tax or earn below £12,570. The higher-earning partner must be a basic-rate taxpayer. In England, Wales, and Northern Ireland that generally means income between £12,571 and £50,270; in Scotland the upper limit is £43,662 because Scottish income tax bands differ.4GOV.UK. Marriage Allowance
If either of you was born before 6 April 1935, Married Couple’s Allowance may be worth more. You can’t claim both.4GOV.UK. Marriage Allowance
Backdating Up to Four Years
Marriage Allowance claims can be backdated by up to four tax years. If you’ve been eligible since 2021/22 but never applied, HMRC can pay out for each missed year.4GOV.UK. Marriage Allowance At £252 a year, backdating four years alongside the current year comes to £1,260. Backdated amounts usually arrive as a cheque or bank transfer, because PAYE for those years has already closed.
How to Apply
The lower earner makes the application, and both partners’ National Insurance numbers are needed. The online route on GOV.UK is the fastest option; a Government Gateway account speeds things up, but identity can also be verified through questions based on your credit record or P60.5GOV.UK. Apply for Marriage Allowance Online A postal claim uses form MATCF.6GOV.UK. Apply for Marriage Allowance by Post
Once processed, both partners’ tax codes are updated to reflect the transfer.7HM Revenue & Customs. PAYE Manual – Coding: Suffix Codes Take-home pay usually reflects the change within two to six weeks of a digital submission.
When You Have to Cancel Marriage Allowance
The transfer doesn’t quietly stop when your situation changes. You have to actively cancel it in several cases, and failing to do so can leave one of you with an incorrect tax bill.8GOV.UK. Marriage Allowance: If Your Circumstances Change
- Divorce or separation: either partner can cancel, and the change can be backdated to the start of the tax year.
- Death of the higher earner: their estate keeps the increased allowance, and the transferor reverts to the standard amount.
- Death of the lower earner: the higher earner keeps the extra allowance until 5 April, then it ends automatically.
- Income changes taking either partner outside the qualifying range.
One point catches people out: leaving the Marriage Allowance section blank on a Self Assessment return does not cancel the transfer. You have to cancel separately, online or by phoning 0300 200 3300.8GOV.UK. Marriage Allowance: If Your Circumstances Change
Blind Person’s Allowance Transfers More Fully
Blind Person’s Allowance behaves differently from the standard Personal Allowance in one respect that matters here: if you qualify and can’t use all of it against your own income, the entire unused portion can be transferred to a spouse or civil partner, not just a fixed slice. For 2026/27 the allowance is £3,250, which makes it a more valuable transfer than Marriage Allowance for those who qualify. Eligibility means being registered as severely sight impaired with your local authority, or, in Scotland, being unable to do any work for which eyesight is essential.
What You Cannot Do With Unused Allowance
- Roll it over to the next tax year. No mechanism exists; it expires on 5 April.
- Transfer it to anyone other than a spouse or civil partner. Parents, children, and unmarried partners are not eligible recipients.
- Choose the transfer amount. Marriage Allowance is a fixed £1,260, regardless of how much allowance you actually left unused.
- Combine multiple years into one boosted allowance. Backdated claims apply year by year; they don’t stack into a single larger figure.
The practical takeaway: use your Personal Allowance within the tax year or lose it. If you’re married or in a civil partnership and consistently earn below £12,570, applying for Marriage Allowance — and backdating it as far as you’re entitled to — is the single step that stops at least part of the allowance from going to waste.