Marriage Allowance: how to back-claim for previous tax years

Marriage Allowance works by transferring £1,260 of your personal allowance (£12,570 for 2026-27) to your spouse or civil partner, provided you meet all of the following criteria: you are married or in a civil partnership; one partner is a basic rate taxpayer (paying 20% income tax) and the other partner earns less than their personal allowance (under £12,570); and both partners are born after 6 April 1935. The recipient partner must be a Scottish or English/Welsh taxpayer — the rules differ for Scottish taxpayers. The transfer is worth £252 per year (£1,260 × 20%) in income tax reduction. The transferrer does not lose the personal allowance entirely — they retain £11,310 of their own allowance.

If you have been eligible for Marriage Allowance but have not claimed it, you can back-claim for up to four previous tax years. Contact HMRC directly to make a back-claim — you can do this by phone, by post, or through your Personal Tax Account on Gov.uk. You will need to provide details of both partners' National Insurance numbers and dates of birth. HMRC will calculate the refund due for each year and pay it directly to the recipient partner. As of 2026-27, you can back-claim for 2022-23, 2023-24, 2024-25, and 2025-26 if you became eligible in those years. The maximum back-claim is typically four years, so if you first became eligible in the 2022-23 tax year, you can back-claim for that year and claim for the current year going forward.

The Marriage Allowance is worth £252 per year (£1,260 × 20%) in income tax reduction. If you back-claim for four previous tax years plus the current year, the maximum total value is £1,260 (£252 × 5 years). However, the back-claim amount for previous years depends on whether you were eligible in those specific tax years and whether either partner's tax band changed. The simplest way to calculate your potential back-claim is to use HMRC's Marriage Allowance calculator on Gov.uk, which will tell you your eligibility and the total amount you could claim. If either partner's income crossed the personal allowance threshold in any of the previous years, the claim amount for those years may be reduced or not applicable.