Guide · 4 minute read · Updated 10 Jul 2026

Can I claim Marriage Allowance and how much is it worth?

Marriage Allowance lets one partner hand 10% of their personal allowance to the other, cutting the couple's tax by up to £252 a year. It only works when one of you earns too little to use their full allowance and the other is a basic-rate taxpayer, but if that is you, it is close to free money.

What Marriage Allowance actually does

Everyone gets a personal allowance of £12,570 they can earn before paying income tax. If one partner earns less than that, part of their allowance goes to waste, because you cannot carry unused allowance forward or get it as cash.

Marriage Allowance fixes that partial waste. The lower earner transfers £1,260 (just over 10% of £12,570) of their allowance to their partner. The partner's own allowance rises by £1,260, so £1,260 of their income that was taxed at 20% becomes tax-free. Twenty per cent of £1,260 is £252, which is the annual saving. It is not a payment to the lower earner; it is a reduction in the higher earner's tax bill, and the couple keeps the difference.

Who qualifies

Three things all need to be true:

• You are married or in a civil partnership. Living together does not count.
• The partner giving up allowance is a non-taxpayer, so their income is below £12,570 (or low enough that giving up £1,260 still leaves them owing no tax).
• The partner receiving it is a basic-rate taxpayer, with income between £12,570 and £50,270.

If the receiving partner is a higher-rate (40%) or additional-rate taxpayer, you generally cannot claim. The design is specifically to move an unused allowance from someone who does not need it to a basic-rate partner who does. The lower earner makes the claim, on GOV.UK, and it is free; ignore any site that offers to do it for a fee.

Backdating: up to about £1,260 back

This is the part people miss. You can backdate a claim by up to four tax years, as long as you qualified in each of them. Claim now and you can reach back to 2022/23.

Four backdated years at £252 each, plus the current year, is over £1,260 as a one-off, paid as a refund (usually a cheque or bank transfer) for the closed years and a tax-code change for the current one. Once claimed, the transfer rolls over automatically each year until you cancel it, so you do not have to reapply. If your circumstances change, for example the receiving partner starts earning enough to become a higher-rate taxpayer, cancel it to avoid an unexpected bill.

The M and N tax codes

You can tell Marriage Allowance is running from the letter on your tax code. The partner who receives the extra allowance has a code ending in M (for example 1383M). The partner who gave up allowance has a code ending in N (for example 1131N).

If your code already ends in M or N, the allowance is in place and you do not need to do anything, including on a Self Assessment return. If you think you qualify but neither of you has an M or N code, the claim has not been made, and that is the £252 a year (plus backdating) sitting on the table. Our tax code checker explains what the letters and numbers on your code mean.

Common questions

How much is Marriage Allowance worth in 2026/27?

Up to £252 a year. One partner transfers £1,260 of their £12,570 personal allowance to the other, making £1,260 of the receiving partner's income tax-free. Twenty per cent of £1,260 is the £252 saving.

Who qualifies for Marriage Allowance?

Married couples and civil partners where one partner is a non-taxpayer (income under £12,570) and the other is a basic-rate taxpayer (income £12,570 to £50,270). You cannot usually claim if the receiving partner pays higher or additional-rate tax.

Can I backdate a Marriage Allowance claim?

Yes, up to four tax years if you qualified in each, reaching back to 2022/23. Combined with the current year that is over £1,260 as a one-off, paid as a refund for closed years and a tax-code change for the current one.

What do the M and N tax code letters mean?

They show Marriage Allowance is active. A code ending in M means you receive the extra £1,260 of allowance; a code ending in N means you transferred it away. If neither partner has an M or N code, the claim has not been made yet.

Guidance and education, not regulated financial advice.