Marriage Allowance
Allows one partner in a marriage or civil partnership to transfer £1,260 of their unused Personal Allowance to the other, reducing the recipient's tax bill by up to £252 per year. The transferring partner must have income below the Personal Allowance, and the recipient must be a basic-rate taxpayer. Claims can be backdated up to four years.
How it works
Marriage Allowance only works in one direction — the lower earner transfers part of their unused Personal Allowance to the higher earner, never the other way round, and both partners must actively agree to the transfer since it changes both of their tax codes. Once claimed, it renews automatically each year unless one of you cancels it or your circumstances change, so you don't need to reapply every year.
You apply through HMRC's online service or by phone, and the recipient's tax code typically changes to show an 'M' suffix while the transferring partner's code shows an 'N' suffix, reflecting the allowance moving between them. Because claims can be backdated up to four years, it's worth checking eligibility even if your circumstances have changed since a qualifying year — you might be owed a refund for allowance you were entitled to but never claimed.
If the higher earner's income later moves into higher-rate territory, or the lower earner's income rises above the Personal Allowance, the couple may lose eligibility and need to cancel the transfer — leaving it in place when you no longer qualify doesn't create an automatic problem, but it can lead to an unexpected tax code adjustment when HMRC later reviews it.
Example: How the £252 saving is worked out
Suppose the lower-earning partner transfers the full £1,260 of unused Personal Allowance to their basic-rate-taxpayer spouse.
That £1,260 becomes tax-free for the recipient instead of being taxed at the basic rate of 20%, saving £1,260 × 20% = £252 for the year — the maximum available saving.
Frequently asked questions
Can Marriage Allowance be backdated?
Yes — you can claim for up to four previous tax years in which you were eligible but didn't apply, potentially generating a lump-sum refund alongside the ongoing saving.
What happens to Marriage Allowance if we divorce or separate?
You need to cancel the transfer, since you're no longer eligible once the marriage or civil partnership ends, though the allowance normally continues until the end of the tax year in which you separate.
Does claiming Marriage Allowance affect the transferring partner's own tax bill?
Yes — the transferring partner's Personal Allowance is reduced by the amount transferred, so if their income later increases, they could end up paying more tax than if they hadn't made the transfer.
Related Terms
Personal Allowance
The amount of income you can earn in a tax year before paying income tax, currently £12,570 and frozen until April 2031 (the freeze was extended by three years at the Autumn Budget 2025).
Basic Rate
The standard income tax rate of 20% applied to taxable income between the Personal Allowance and the higher-rate threshold, currently £12,571 to £50,270 in England, Wales, and Northern Ireland.
Tax Code
A code issued by HMRC to your employer to tell them how much income tax to deduct from your pay each period.
Try the calculator
Use our free tool to see how marriage allowance affects your tax.