Two reliefs with almost identical names but completely different rules. One is a tax reducer for older couples; the other transfers part of a Personal Allowance. Here is which applies to you in 2025/26.
Few areas of UK tax cause as much confusion as the two reliefs available to married couples and civil partners. The names are almost interchangeable in everyday speech, yet Marriage Allowance and Married Couple's Allowance are completely different things, with different eligibility rules, different amounts, and different mechanics. Getting them mixed up is common, and it can mean either claiming the wrong relief or missing out on money you are owed. This guide separates the two cleanly and shows which one applies to you in the 2025/26 tax year.
The single most useful test is date of birth. If you or your spouse were born before 6 April 1935, you are in Married Couple's Allowance territory, the older and more generous of the two reliefs. If you were both born on or after that date, the relief available to you is Marriage Allowance. They cannot both apply to the same couple, so the cut-off does the deciding for you.
Marriage Allowance, introduced in 2015, is the relief most couples encounter today. It lets a spouse or civil partner who earns below the Personal Allowance transfer 10 per cent of that allowance, £1,260 for 2025/26, to their partner, provided the partner is a basic-rate taxpayer.
The mechanics are straightforward. The lower earner gives up £1,260 of their £12,570 Personal Allowance, leaving them with £11,310. The higher earner receives an extra £1,260 of tax-free allowance, which saves them tax at 20 per cent: a maximum benefit of £252 a year. The transfer makes sense only when the lower earner would not have used all of their Personal Allowance anyway, so it is genuinely free.
To qualify for Marriage Allowance in 2025/26:
The relief is reflected in your tax codes. The partner receiving the transferred allowance gets an M suffix on their tax code, and the partner giving it up gets an N suffix. If you have ever wondered why your code ends in M or N, this is why. You can check whether your code reflects a Marriage Allowance claim by reviewing your tax code.
Married Couple's Allowance predates Marriage Allowance by decades and survives only for couples where one partner was born before 6 April 1935, meaning the youngest possible claimant is now in their nineties. It is a tax reducer rather than an allowance transfer, which is a crucial distinction.
Instead of changing how much income is tax-free, MCA reduces the tax bill directly by 10 per cent of an allowance band. For 2025/26 that band ranges from a minimum of £4,280 to a maximum of £11,080. So the tax saving is:
This makes MCA substantially more valuable than Marriage Allowance, which is why couples who qualify should always use it rather than the modern relief.
The maximum allowance is reduced once the higher earner's adjusted net income exceeds £37,700 for 2025/26. For every £2 of income above that threshold, the allowance falls by £1, until it reaches the £4,280 minimum. Importantly, the taper stops there: even a high earner born before April 1935 keeps the minimum £427 tax reduction. The reduction in the Personal Allowance for income over £100,000 can also interact with this, but the MCA minimum is protected.
For marriages that took place before 5 December 2005, the allowance is given to the husband by default, calculated on his income, though couples can elect to transfer the minimum amount or split it. For marriages and civil partnerships from 5 December 2005 onward, it is based on the income of the higher earner.
The table below is the quickest way to see which relief you are dealing with.
| Feature | Marriage Allowance | Married Couple's Allowance |
|---|---|---|
| Who qualifies | Both partners born on/after 6 Apr 1935 | At least one partner born before 6 Apr 1935 |
| Introduced | April 2015 | Long-standing legacy relief |
| Type | Transfer of Personal Allowance | Tax reducer (10% of an allowance) |
| 2025/26 value | Up to £252 saving | £427 to £1,108 saving |
| Lower earner condition | Must earn below £12,570 | No such requirement |
| Tax code effect | M / N suffix | Code adjusted to collect the reducer |
| Can backdate | Up to 4 years | Yes, within normal time limits |
Consider two couples to see the difference in practice.
The Patels are both in their forties. Anita earns £9,000 from part-time work; her husband Raj earns £38,000. Anita does not use her full Personal Allowance, so she transfers £1,260 to Raj under Marriage Allowance. Raj's tax-free amount rises by £1,260, saving the couple £252 (£1,260 x 20%). Anita pays no extra tax because her income stays below her reduced £11,310 allowance. Their net gain is £252 for the year.
The Hardys are both in their nineties; Frank was born in 1933. They qualify for Married Couple's Allowance. Frank's income is £30,000, comfortably below the £37,700 taper threshold, so the full £11,080 allowance applies. Their tax reduction is £11,080 x 10% = £1,108 for the year, more than four times what the younger couple receives. Frank could not claim Marriage Allowance as well; the two are mutually exclusive, and MCA is the better deal in any case.
Neither relief operates in a vacuum, and a few interactions are worth understanding.
Both partners still have their standard £12,570 Personal Allowance as the starting point. For higher earners, the Personal Allowance is reduced by £1 for every £2 of income over £100,000, disappearing entirely at £125,140. This taper can reduce the value of a Marriage Allowance transfer if the receiving partner's income approaches £100,000, and it interacts with the MCA income limits for very high earners, though the MCA minimum reduction is preserved.
Marriage Allowance only works while the receiving partner remains a basic-rate taxpayer. If their income rises into the higher-rate band, the couple is no longer eligible and the transfer should be cancelled, otherwise HMRC will claw it back. Scottish taxpayers are eligible if the receiving partner is a starter, basic or intermediate-rate taxpayer.
Married Couple's Allowance can be combined with Blind Person's Allowance, and surplus Blind Person's Allowance can be transferred between spouses in the same way, which can further reduce an older couple's tax bill.
The decision tree is short. If either of you was born before 6 April 1935, claim Married Couple's Allowance: it is worth far more and the date-of-birth condition rules out Marriage Allowance anyway. If you were both born on or after 6 April 1935, your route is Marriage Allowance, and it is worth claiming whenever one partner's income falls below the Personal Allowance while the other is a basic-rate taxpayer.
Two reliefs, one shared name, and a date in 1935 that decides everything. The couples who lose out are usually the ones who assumed the names meant the same thing and never checked.
If you are unsure which relief is reflected in your situation, the fastest check is your tax code. An M or N suffix points to Marriage Allowance; checking your tax code will tell you whether a claim is already in place and whether it looks correct for your circumstances.
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