UK Tax Codes · 2026/27
M Tax Code Meaning — Marriage Allowance (UK 2026/27)
Who gets the M (Marriage Allowance recipient) tax code?
M applies to people who receive Marriage Allowance from a spouse/civil partner. Eligibility: the giver must earn below £12,570 personal allowance; the receiver (you) must earn between £12,570 and £50,270 (basic-rate band). Both must apply via HMRC. Around 4 million UK couples qualify; only about 2 million actually claim, leaving £252/year unclaimed by the rest.
How M (Marriage Allowance recipient) affects your pay
M adds £1,260 to your personal allowance, so the first £13,830 of earnings is tax-free instead of £12,570. Saves you 20% × £1,260 = £252 per year. The savings continue automatically each year unless you cancel or your circumstances change.
When to check this code
Check M if you've recently married or entered a civil partnership and one of you earns below the personal allowance. Also check after any change in either partner's income — M becomes invalid if your income drops below £12,570 (you can't be the recipient) or your partner's income rises above the personal allowance.
What to do if it's wrong
If M is showing but you're not claiming Marriage Allowance, check with your spouse — they may have applied without telling you (it's mutual). If M is missing but you should be receiving it, apply via HMRC online or by phone. Backdated claims are possible for up to 4 previous tax years.
Example calculation
On £30,000 with 1383M: first £13,830 tax-free; the rest £16,170 taxed at 20% = £3,234 income tax. Compare to 1257L: £3,486 tax. The 1383M saves you £252/year.
Recruiter pro tip
Marriage Allowance is one of the most under-claimed UK tax benefits — about £200 million unclaimed each year because eligible couples don't apply. If one of you earns below £12,570 (e.g. part-time, on parental leave, between jobs) and the other earns under £50,270, claim it. Backdated claims can recover up to £1,008 across 4 years.
Related tax codes
N — Marriage Allowance Transfer
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1257L
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BR — Basic Rate
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