How Marriage Allowance works
It's a transfer of unused personal allowance, not a marriage subsidy. The personal allowance for 2025/26 is £12,570 - the amount you can earn before paying any income tax. If one partner earns less than £12,570, they don't fully use it.
Marriage Allowance lets the lower earner transfer £1,260 (10% of the personal allowance, fixed) to their spouse. The receiving partner's personal allowance becomes £13,830, saving them 20% × £1,260 = £252 in income tax per year.
It's a flat £252 - it doesn't scale with the donor's income, and it doesn't scale with the receiver's income (as long as they're a basic-rate taxpayer earning between £12,570 and £50,270).
Eligibility: who qualifies
You both need to:
• Be married or in a civil partnership (cohabiting partners don't qualify, however long together) • Be UK residents (some EEA/Swiss residents qualify too) • The lower earner: total income (salary + pensions + savings + dividends) under £12,570 for the tax year • The higher earner: total income between £12,570 and £50,270 (basic-rate band)
What counts as "income": salary, pensions, rental, savings interest above the £1,000 PSA, dividends above the £500 dividend allowance, and self-employment profit.
Does NOT qualify: if either of you pays higher rate (40%) or additional rate (45%). One exception: the Scottish equivalent applies to Scottish residents earning under £43,662 (basic rate ceiling in Scotland is different).
Backdating: claim up to 4 years
You can backdate Marriage Allowance to any tax year still within the 4-year reclaim window where you would have qualified. Tax year 2021/22 closes April 2026 - claim before then for the £252 refund.
A fresh claim made in May 2026 can backdate to: • 2021/22: £252 (closing soon!) • 2022/23: £252 • 2023/24: £252 • 2024/25: £252 • 2025/26 (current): £252 going forward via tax code
Total one-off refund: £1,008 (2021/22-2024/25), plus £252 saved going forward via tax code adjustment.
HMRC pays backdated refunds either as a tax code adjustment over the next 12 months or as a one-off bank transfer (their choice).
Tax codes: 1131M and 1383N explained
When approved, HMRC adjusts both partners' tax codes:
• Donor (lower earner): code becomes 1131N. The N suffix means "transferred allowance OUT". Personal allowance reduced from £12,570 to £11,310.
• Receiver (higher earner): code becomes 1383M. The M suffix means "received transferred allowance". Personal allowance increased from £12,570 to £13,830.
This is automated - no need to apply each year. The transfer continues until one of you cancels (e.g., income changes, separation).
If you split up: the transfer continues until end of the current tax year, then auto-cancels. You don't need to back-pay anything.
How to claim: 10-minute online application
Apply via gov.uk → "Marriage Allowance" → "Apply now" - the lower earner submits the application. You'll need:
• Both partners' National Insurance numbers • Both partners' details for one of: P60, payslip, passport, or 3 questions about your tax history
After submission: • HMRC sends confirmation by post within 2-4 weeks • Backdated refunds processed in 6-8 weeks (often faster) • Tax codes auto-update within 1 pay period for current year savings
Common mistakes:
1. Wrong partner applies: only the LOWER earner can transfer. The higher earner can't initiate the claim.
2. Self-employed savings interest: small bits of bank interest can push you above £12,570 and disqualify the claim. Check before applying.
3. Don't cancel when one starts higher rate: if a promotion takes the receiver above £50,270, the transfer becomes invalid for that year - they must cancel or HMRC will claw it back via Self Assessment.
Run the math for your situation
Use our 🇬🇧 UK calculator to plug in your own numbers and see exactly what you owe / save.