If you’re married or in a civil partnership and one of you earns less than the other, there’s a decent chance HMRC owes you money. Not because you overpaid tax by mistake — but because there’s a specific allowance built into the tax system that millions of eligible couples simply never apply for.
It’s called Marriage Allowance, and it lets a lower-earning partner hand over a slice of their unused tax-free allowance to their spouse or civil partner. Done right, it’s worth up to £252 a year, every year, for as long as you both qualify. And because you can backdate claims, some couples get a lump sum worth several hundred pounds the first time they apply.
This isn’t a loophole or a trick. It’s a standard HMRC allowance that exists specifically for couples in your situation — it just doesn’t apply automatically. You have to ask for it.
What Marriage Allowance actually is
Everyone in the UK gets a Personal Allowance — the amount you can earn each year before you start paying Income Tax. It’s currently frozen at £12,570. If you earn below that, you don’t pay any Income Tax at all.
Marriage Allowance lets the lower earner transfer 10% of their Personal Allowance — £1,260 — to their husband, wife, or civil partner. The partner receiving it gets a bigger tax-free allowance, which means more of their income is taxed at 0% instead of 20%. Transfer £1,260 of allowance, and the receiving partner pays up to £252 less tax that year (that’s £1,260 taxed at the 20% basic rate, saved).
The person giving up the allowance doesn’t lose anything in practice — if they’re earning below the Personal Allowance anyway, that unused chunk would otherwise just go to waste.
Who actually qualifies
This is where most people either rule themselves out wrongly, or assume they qualify when they don’t. The rules are specific:
- You must be married or in a civil partnership — living together without either doesn’t count, regardless of how long you’ve been a couple.
- One partner must earn less than the Personal Allowance (£12,570) — including anyone earning nothing at all, such as a stay-at-home parent or someone not currently working.
- The other partner must be a basic rate taxpayer — meaning their income falls between £12,571 and £50,270 (or £43,662 in Scotland, where tax bands differ). If they’re a higher or additional rate taxpayer, you can’t claim.
- Both of you must have been born on or after 6 April 1935 (there’s a separate, older allowance — Married Couple’s Allowance — for couples born before this date).
If the higher earner is a higher-rate taxpayer, Marriage Allowance isn’t available to you, even if the other partner has unused allowance sitting there unused.
The misconception that stops people claiming
The most common reason people don’t apply: they assume it only applies if one partner isn’t working at all. That’s not true. The test is about income level, not employment status.
Someone working part-time on £9,000 a year, someone on maternity or paternity leave with reduced pay, someone semi-retired and drawing a small pension, or someone self-employed with low profits one year — all of these can qualify as the lower earner, as long as their total taxable income is under £12,570.
The second misconception: people think it’s a joint tax return or some complicated reassessment. It isn’t. It’s a single online form, takes about ten minutes, and HMRC adjusts both of your tax codes automatically.
How much it’s actually worth
| Scenario | Allowance transferred | Approximate tax saving |
|---|---|---|
| Current tax year only | £1,260 | Up to £252 |
| Backdated 1 previous year | £1,260 (x2 years) | Up to £504 total |
| Backdated 4 previous years + current year | £1,260 (x5 years) | Up to £1,260 total |
You can backdate a claim by up to four tax years, as long as you were eligible in each of those years. That’s why some couples who’ve never claimed before suddenly get a backdated payment of £500–£1,000+ the first time they apply, on top of the ongoing saving going forward.
The exact figure depends on the allowance amount in each specific tax year, which has varied slightly over time, but £1,260 has been the figure for several recent years.
How to actually claim it
The claim has to come from the lower earner — the person giving up part of their allowance, not the person receiving it. This trips people up constantly.
- Go to gov.uk’s Marriage Allowance page and apply online — it’s free, and this is the only official route. (Some third-party websites charge a fee to “process” your claim for you — you don’t need them.)
- You’ll need both National Insurance numbers, and proof of identity for the person applying (such as the last 4 digits of a bank account, a passport number, or a P60).
- Confirm the tax years you want to apply for, including any backdated years you were eligible.
- HMRC adjusts tax codes. If you’re both employed through PAYE, you’ll usually see the change reflected in your tax code within a few weeks. Any backdated amount typically comes as a cheque or bank payment rather than a tax code adjustment, since it relates to a year already finished.
Once you’ve claimed, you don’t need to reapply every year — it continues automatically unless your circumstances change (for example, your income rises above the threshold, or you separate or divorce).
What happens if your circumstances change
Marriage Allowance isn’t a one-off decision you make and forget. If the lower earner’s income increases above £12,570, or the higher earner moves into higher-rate tax, you need to tell HMRC — the allowance should be cancelled, because you no longer qualify.
If you separate, divorce, or your civil partnership ends, you also need to cancel the claim. Failing to update HMRC can mean an incorrect tax code and an unexpected tax bill later, because HMRC will eventually catch the mismatch and claw back what you weren’t entitled to.
You can check or cancel your claim through your personal tax account on gov.uk.
Why this gets missed so often
Marriage Allowance isn’t advertised much, it’s not something your employer flags, and unlike a pay rise or a bonus, nobody tells you it’s sitting there unclaimed. It also sits in an odd gap — it’s not relevant to single people, so it doesn’t come up in general money advice, and it’s easy to assume (wrongly) that HMRC would apply it automatically if you qualified.
It won’t apply itself, no matter how long you’ve been eligible. The only way to get it is to submit the claim yourself.
The bottom line
- Check whether you qualify this week: one of you earning under £12,570, the other a basic rate taxpayer, and you’re married or in a civil partnership.
- If you qualify now and have qualified for previous years too, claim the backdated years in the same application — it’s the same ten-minute process either way.
- Apply only through gov.uk directly — never pay a third party to submit this for you.
- Set a reminder to review eligibility once a year, particularly after a pay rise, a new job, or a change in working hours for either of you.
- If you separate or your income changes mid-year, update HMRC promptly to avoid a tax code mismatch and a surprise bill down the line.
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