Marriage Allowance Calculator (UK 2026)

Marriage Allowance Guide 2026/27

How It Works?

Marriage Allowance allows the lower-earning spouse to transfer £1,260 (10% of the £12,570 personal allowance) to their higher-earning spouse. The higher earner gets this £1,260 added to their personal allowance — saving 20% tax on £1,260 = £252 per year. Eligibility requirements: married or in a civil partnership (cohabiting NOT eligible). One partner earns under the Personal Allowance (£12,570 for 2026/27). Other partner is a basic rate taxpayer (earnings £12,571 to £50,270). Both born after 5 April 1935 — those born before this date may benefit more from the older Married Couple's Allowance instead.

What do I need to know about Who Benefits Most?

Maximum benefit: one partner not working, other earning £20,000-£50,270. Saves full £252 per year. Real savings depend on how much of the lower earner's personal allowance is unused. If lower earner earns £8,000: £4,570 of allowance unused. They can transfer £1,260 (the maximum), saving the full £252. If lower earner earns £12,000: £570 of allowance unused. Still beneficial — transferring £1,260 only 'costs' the lower earner up to £570 × 20% = £114 of tax (they would otherwise pay no tax). Net household gain: £252/year (the higher earner's tax saving) minus £114 (the lower earner's lost relief) = £138/year — still worthwhile, but smaller than the headline £252 figure suggests once the lower earner's own position is factored in.

What should I know about Backdating?

You can backdate Marriage Allowance claims up to 4 tax years. For 2026/27 claim, you can backdate to 2020/21, 2021/22, 2022/23, 2023/24. Each year saves up to £252 (rates have varied slightly: 2020/21 £250, 2021/22 £252, etc). Total backdated refund: up to £1,000+. The backdated amount is paid as a cheque or BACS transfer when first claim is approved. Future years are applied automatically by adjusting tax codes. Beware of third-party 'tax refund companies' that charge 25-40% commission to claim Marriage Allowance on your behalf — the application is free and takes minutes directly through HMRC, so there's no need to pay anyone to do it for you.

How to Apply?

Apply directly at gov.uk/marriage-allowance. You need: National Insurance numbers for both partners. Proof of identity (passport, P60). Once approved: tax code changes apply to higher earner (e.g. from 1257L to 1383M, where M indicates Marriage Allowance recipient). Lower earner's tax code becomes 1131N (N indicates transfer to partner). Cancellation: contact HMRC if relationship ends or income changes. Otherwise, Marriage Allowance continues year to year automatically. Important: must be reclaimed each year if backdating multiple years — HMRC does not automatically apply it retroactively to earlier tax years without a specific claim for each one.