Marriage Allowance Calculator (UK 2026)

Marriage Allowance Guide 2026/27

How It Works?

Marriage Allowance allows the lower-earning spouse to transfer £1,260 (10% of the £12,570 personal allowance) to their higher-earning spouse. The higher earner gets this £1,260 added to their personal allowance — saving 20% tax on £1,260 = £252 per year. Eligibility requirements: married or in a civil partnership (cohabiting NOT eligible). One partner earns under the Personal Allowance (£12,570 for 2026/27). Other partner is a basic rate taxpayer (earnings £12,571 to £50,270). Both born after 5 April 1935 — those born before this date may benefit more from the older Married Couple's Allowance instead.

What do I need to know about Who Benefits Most?

Maximum benefit: one partner not working, other earning £20,000-£50,270. Saves full £252 per year. Real savings depend on how much of the lower earner's personal allowance is unused. If lower earner earns £8,000: £4,570 of allowance unused. They can transfer £1,260 (the maximum), saving the full £252. If lower earner earns £12,000: £570 of allowance unused. Still beneficial — transferring £1,260 only 'costs' the lower earner up to £570 × 20% = £114 of tax (they would otherwise pay no tax). Net household gain: £252/year (the higher earner's tax saving) minus £114 (the lower earner's lost relief) = £138/year — still worthwhile, but smaller than the headline £252 figure suggests once the lower earner's own position is factored in.

What should I know about Backdating?

You can backdate Marriage Allowance claims up to 4 tax years. For 2026/27 claim, you can backdate to 2020/21, 2021/22, 2022/23, 2023/24. Each year saves up to £252 (rates have varied slightly: 2020/21 £250, 2021/22 £252, etc). Total backdated refund: up to £1,000+. The backdated amount is paid as a cheque or BACS transfer when first claim is approved. Future years are applied automatically by adjusting tax codes. Beware of third-party 'tax refund companies' that charge 25-40% commission to claim Marriage Allowance on your behalf — the application is free and takes minutes directly through HMRC, so there's no need to pay anyone to do it for you.

How to Apply?

Apply directly at gov.uk/marriage-allowance. You need: National Insurance numbers for both partners. Proof of identity (passport, P60). Once approved: tax code changes apply to higher earner (e.g. from 1257L to 1383M, where M indicates Marriage Allowance recipient). Lower earner's tax code becomes 1131N (N indicates transfer to partner). Cancellation: contact HMRC if relationship ends or income changes. Otherwise, Marriage Allowance continues year to year automatically. Important: must be reclaimed each year if backdating multiple years — HMRC does not automatically apply it retroactively to earlier tax years without a specific claim for each one.

How Marriage Allowance Transfers a Slice of Unused Personal Allowance

Marriage Allowance lets a lower-earning spouse or civil partner, who isn't using their full personal allowance, transfer a fixed portion of that unused allowance to their partner, reducing the receiving partner's tax bill by a set amount — provided the receiving partner is a basic-rate taxpayer (not a higher or additional-rate taxpayer, who would not benefit and in fact cannot receive the transfer). This only produces a saving when one partner earns below the personal allowance threshold (or has no income at all) and the other earns enough to actually use the transferred amount, which is why it typically suits couples with one non-earning or low-earning partner and one earning a moderate, basic-rate income — not two working partners both already comfortably using their own full allowance.

Why Many Eligible Couples Still Haven't Claimed It

Marriage Allowance claims can typically be backdated for several previous tax years in addition to the current one, provided the eligibility conditions were met in each of those years, which means a couple who only discovers the allowance exists can often claim a meaningful lump sum covering multiple years of missed saving in a single backdated claim, not just going forward from the claim date. Because the saving is relatively modest in any single year and the eligibility criteria — one partner below the personal allowance, the other a basic-rate taxpayer — require actively checking rather than being automatically applied, a significant number of genuinely eligible couples simply never get around to claiming it, which is why checking eligibility explicitly, even for a seemingly small annual saving, is worth the few minutes it takes.

What Happens to Marriage Allowance in the Year of Divorce or Death

Marriage Allowance doesn't necessarily end the moment a marriage or civil partnership legally ends, because the transfer can continue to apply for the tax year in which the separation, divorce, or death occurs, depending on timing and whether the transfer has already been set up. If a couple divorces partway through a tax year, the transferred allowance generally continues to apply for that tax year, since the allowance is assessed on an annual basis rather than prorated for the exact number of days the marriage lasted within it, though either party can ask HMRC to cancel the transfer going forward from the point they're no longer together if they'd prefer not to continue it. Where one partner dies while the transfer is in place, the surviving partner generally keeps the benefit of the transfer for that tax year, and the allowance can also be backdated for the deceased partner's estate for earlier eligible years that were never claimed, in the same way backdating works for a living couple who simply hadn't applied earlier. Because Marriage Allowance is reassessed year by year rather than being a one-off permanent election, a couple who separate and don't formally cancel the transfer should check whether it's still correctly reflected in both parties' tax codes going forward, to avoid one person's tax code carrying an allowance adjustment that no longer reflects their actual situation.

Worked Example: Transferring the Full Allowance

A couple has one partner earning £8,000 a year (well below the personal allowance, with £4,570 of unused allowance assuming a typical £12,570 personal allowance) and the other earning £32,000, comfortably a basic-rate taxpayer. Marriage Allowance lets the lower earner transfer a fixed 10% of their personal allowance — not the full unused amount — to their spouse, typically around £1,260. The higher-earning partner's tax bill is reduced by 20% of that transferred amount (since it effectively increases their own tax-free allowance), giving a saving of roughly £252 a year. This is a flat cash saving regardless of exactly how much of the lower earner's allowance was otherwise going unused — the lower earner could have £1,000 or £4,000 of spare allowance, and the transferable amount and resulting saving are the same fixed £1,260/£252 figures, because Marriage Allowance transfers a fixed 10% slice, not a variable "whatever's unused" amount. Couples where the lower earner has only a small amount of spare allowance (say, £500) still get the same £252 saving, which is why eligibility — being married or in a civil partnership, with one partner a non-taxpayer or low earner and the other a basic-rate taxpayer — matters more to check than trying to calculate "how much is unused" precisely.

Reference: Marriage Allowance Value by Personal Allowance

The transferable amount is fixed as a proportion of the standard Personal Allowance for the tax year, rounded to a convenient figure by HMRC, rather than a number either partner chooses — so the saving moves only when the government changes the underlying Personal Allowance or the transfer percentage itself, both of which should be checked for the current tax year rather than assumed to stay the same indefinitely.

What Happens If the Lower Earner Starts Paying Tax Later

Marriage Allowance is designed around the lower earner having income below, or not far above, the Personal Allowance, so if their income rises during the tax year — a new job, a pay rise, or extra hours — and they end up needing more of their own allowance, the transfer can still go through, but it may now mean the lower earner owes some tax themselves or receives a smaller refund than expected, since part of their own tax-free allowance has already been given to their partner. The claim can be cancelled going forward if circumstances change permanently, but it generally continues automatically year to year until either partner cancels it or a change in circumstances, like divorce, ends eligibility, so it's worth reviewing the claim if the lower earner's income situation shifts meaningfully.