If you're married or in a civil partnership and one of you earns under £12,570, the taxman may owe you £252 a year, and up to £1,008 more in backdated years. Check in seconds.
The lower earner transfers £1,260 of their personal allowance to their partner, and the partner's tax bill falls by 20% of it: £252 a year. To qualify, you must be married or in a civil partnership, the lower earner must earn under £12,570, and the higher earner must pay no more than basic rate: up to £50,270, or £43,662 in Scotland.
Two details most pages skip. First, claims backdate up to 4 tax years (to 2022/23), each worth £252, so a first claim can be worth £1,260 in total. Second, if the lower earner makes between £11,310 and £12,570, the transfer costs them a little tax of their own, so the true household gain is smaller than £252. This calculator nets that off rather than pretending it away.
Sources: gov.uk Marriage Allowance (2026/27). Apply free at gov.uk; never pay a claims firm a cut of your own refund.
Illustrative only, not financial or tax advice. Assumes standard tax codes, no Married Couple's Allowance (for couples where one partner was born before 6 April 1935, that is usually worth more and replaces this), and income mainly from earnings or pensions; savings and dividend income can change the sums. Backdated years each assume you met the rules in that year. Always check your own position at gov.uk.
Pairs with Take-Home Pay and the full 2026/27 tax rates.