Marriage Allowance Calculator UK 2025–26
Check if you are eligible and calculate how much tax you could save by transferring part of your Personal Allowance to your spouse or civil partner. Civil partnerships also qualify.
How Marriage Allowance works
Marriage Allowance was introduced in April 2015 to reduce the tax burden on couples where one partner earns significantly less than the other. The lower earner can transfer exactly 10% of their Personal Allowance — £1,260 in 2025–26 — to the higher earner. This creates a tax credit of £252 (£1,260 at the basic rate of 20%) applied directly against the higher earner's tax bill.
The mechanism works through HMRC tax codes. When you apply, the transferor's tax code is reduced from 1257L to 1131L, reflecting that they now have a Personal Allowance of £11,310 rather than £12,570. The transferee receives a corresponding tax credit which is applied by their employer or pension provider through an adjusted tax code.
Unlike some reliefs, Marriage Allowance is a fixed amount — you cannot transfer more or less than 10% of the standard Personal Allowance. In 2025–26, the standard Personal Allowance is £12,570, so the transferable amount is exactly £1,260, producing a saving of exactly £252.
To be eligible, the lower earner must have income below the Personal Allowance (£12,575 for 2025–26). This includes employment income, pension income, rental income, and savings interest above the Personal Savings Allowance. The higher earner must be a basic rate taxpayer — their income must fall between £12,575 and £50,270. Anyone paying 40% or 45% tax does not qualify, because the credit is calculated at 20% and a higher-rate taxpayer would receive a disproportionate benefit.
Applying is straightforward: go to gov.uk/apply-marriage-allowance and complete the online form. HMRC will update both tax codes automatically. If one of you is self-employed, the credit appears on the Self Assessment return instead. Claims can be backdated up to four full tax years, meaning couples who were eligible from 2021–22 could claim up to £1,008 in backdated relief.
The claim must be renewed each year, though HMRC now sends automatic reminders and in many cases continues the transfer automatically unless you cancel it. If your circumstances change — for example the lower earner starts earning above the Personal Allowance, or the higher earner moves into the higher rate band — you should cancel the transfer to avoid an unexpected tax bill.
Frequently asked questions
What is Marriage Allowance?
Marriage Allowance lets you transfer 10% of your Personal Allowance (£1,260 in 2025–26) to your spouse or civil partner. This reduces their tax bill by up to £252 per year. It was introduced in April 2015 and applies across England, Wales, Northern Ireland, and Scotland.
Who is eligible for Marriage Allowance?
To be eligible, you must be married or in a civil partnership. The lower earner must have income below the Personal Allowance (£12,575 in 2025–26). The higher earner must be a basic rate taxpayer — earning between £12,575 and £50,270. If either partner pays higher or additional rate tax, you do not qualify.
How does the tax saving work?
The lower earner (transferor) gives up £1,260 of their unused Personal Allowance. The higher earner (transferee) receives a tax credit of £252 (£1,260 × 20%). HMRC adjusts both tax codes — the transferor's code reduces from 1257L to 1131L, and the transferee's code increases to reflect the credit.
Can I backdate a Marriage Allowance claim?
Yes. You can backdate your claim for up to four tax years. This means you could potentially claim a total of £1,008 or more if you have been eligible since 2021–22 but never claimed. The backdated refund is paid by cheque or bank transfer from HMRC.
Do civil partners qualify for Marriage Allowance?
Yes. Civil partnerships qualify in exactly the same way as marriages. The same eligibility rules apply — one partner must earn below the Personal Allowance and the other must be a basic rate taxpayer. Cohabiting couples who are not married or in a civil partnership do not qualify.
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This calculator provides estimates only. Results are based on the 2025–26 tax year. Credibrate is not a tax adviser. For personalised advice speak to a qualified accountant.