A tax code ending in M means you have received Marriage Allowance from your spouse or civil partner, and a code ending in N means you have transferred it to them. For 2026 to 2027 the transfer is £1,260 of Personal Allowance, which cuts the receiving partner’s tax by up to £252, and a claim can be backdated to 6 April 2022.
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What do M and N mean at the end of a tax code?
The letter at the end of a tax code is the suffix. Gov.uk explains M as “Marriage Allowance: you’ve received a transfer of 10% of your partner’s Personal Allowance” and N as “Marriage Allowance: you’ve transferred 10% of your Personal Allowance to your partner”. HMRC’s PAYE Manual uses the same rule when it sets the suffix. Most people without Marriage Allowance have the suffix L instead, as in 1257L.
The suffix does not change the rates your employer uses. Both M and N codes are taxed at basic, higher and additional rates depending on taxable income, in the same way as an L code. A Scottish or Welsh taxpayer would also have an S or C at the start, as explained in S and C tax codes.
How much is Marriage Allowance worth in 2026 to 2027?
Marriage Allowance lets the lower earner transfer £1,260 of their Personal Allowance to their husband, wife or civil partner. That reduces the partner’s tax by up to £252 in the tax year, which runs from 6 April to 5 April. The standard Personal Allowance for 2026 to 2027 is £12,570. For the basics of the allowance itself, see the Personal Allowance explained, and for the claim process see our main guide to Marriage Allowance.
| Item | 2026 to 2027 |
|---|---|
| Standard Personal Allowance | £12,570 |
| Amount transferred | £1,260 |
| Maximum tax saving for the couple | £252 |
| Transferring partner’s income | Below their Personal Allowance, usually £12,570 |
| Receiving partner (England, Wales, Northern Ireland) | Basic rate, usually income £12,571 to £50,270 |
| Receiving partner (Scotland) | Starter, basic or intermediate rate, usually income £12,571 to £43,662 |
| Earliest backdating | 6 April 2022 |
| Code suffix | M for the receiver, N for the transferor |
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Who qualifies for Marriage Allowance?
- You must be married or in a civil partnership. Couples who live together but are not married or in a civil partnership cannot claim.
- The partner transferring the allowance must not pay Income Tax or must have income below their Personal Allowance, usually £12,570.
- The receiving partner must pay Income Tax at the basic rate, which usually means income between £12,571 and £50,270. In Scotland they must pay the starter, basic or intermediate rate, usually income between £12,571 and £43,662. Our page on Marriage Allowance for Scottish taxpayers covers that version.
- You cannot get Marriage Allowance and Married Couple’s Allowance at the same time. If either of you was born before 6 April 1935, gov.uk suggests you might benefit more as a couple from Married Couple’s Allowance.
How does the code change after you apply?
HMRC gives the receiving partner the extra allowance either by changing their tax code, which can take up to 2 months, or when they send a Self Assessment tax return. If the application succeeds, the change is backdated to the start of the tax year on 6 April. From then on the receiver’s code ends in M and the transferor’s code ends in N.
You do not need to reapply each year. The allowance transfers automatically every year until you cancel it, for example because your income changes or the relationship ends.
How does the number in an M or N code work?
The number in a code tells payroll how much tax free income you get from that job or pension. HMRC starts with the Personal Allowance, adds or takes away adjustments, then replaces the final digit with a letter. Gov.uk’s own example is a £1,570 medical insurance benefit taken from £12,570, which leaves £11,000 and gives the code 1100L.
Illustration only. Leah earns £9,000 a year working part time and Tom earns £32,000. Leah’s income is below her Personal Allowance, so she transfers £1,260 to Tom. Following the method above with no other adjustments, Tom’s tax free amount becomes £13,830 and his code could read 1383M, while Leah’s falls to £11,310, which could read 1131N. Leah still pays no tax because her income stays below £11,310, and Tom’s tax for the year falls by up to £252. Their actual codes will depend on anything else HMRC needs to include, such as benefits or untaxed income.
Can you backdate Marriage Allowance?
Yes. You can backdate a claim to 6 April 2022, the 2022 to 2023 tax year, for any years you were eligible. The Personal Allowance was £12,570 in each year from 2022 to 2023 to 2026 to 2027, and the reduction for each backdated year depends on the allowance for that year. If you are backdating by post you must use form MATCF, because other postal claims are not accepted; if you are not backdating, applying online is quicker.
If your partner has since died, you can backdate a claim by calling the Income Tax helpline. Our guide to Marriage Allowance after a partner dies explains what happens next.
What if your income changes?
The rules apply year by year. If the transferring partner’s income rises above their Personal Allowance, or the receiving partner moves above the basic rate band (or the intermediate rate band in Scotland), the conditions are no longer met and you should cancel. Because the transfer runs automatically until you do, leaving it in place could lead to the wrong tax being collected through the M and N codes. If a code looks wrong, our guide on correcting a wrong tax code shows how to raise it.
Frequently asked questions
Does an M code mean I get more take home pay?
Usually a little. The transfer reduces the receiving partner’s tax by up to £252 over the 2026 to 2027 tax year, collected through a higher tax free amount in the M code.
Do we have to reapply every year?
No. The allowance transfers automatically each year until one of you cancels it.
Can unmarried couples get an M or N code?
No. Gov.uk says you cannot claim Marriage Allowance if you live together but are not married or in a civil partnership.
How far back can we claim?
To 6 April 2022, the start of the 2022 to 2023 tax year, for any years you were eligible.
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Sources
- GOV.UK: What your tax code means
- GOV.UK: manual page PAYE11045
- GOV.UK: Letters
- GOV.UK: Marriage allowance
- GOV.UK: Income tax rates
- GOV.UK: How to apply
- GOV.UK: Income tax personal allowance and the basic rate limit from 6 april 20
- GOV.UK: Income tax rates and allowances current and past
- GOV.UK: Apply for marriage allowance by post
Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 November 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.