Answers · UK 2025/26
Does claiming Marriage Allowance change my tax code?
Yes. When you claim Marriage Allowance, HMRC changes both partners' tax codes. The lower earner who transfers GBP 1,260 of Personal Allowance usually gets an 'N' suffix code, and the higher earner who receives it gets an 'M' suffix code, which is how the GBP 252 yearly saving is delivered through PAYE.
Full answer
Marriage Allowance lets a non-taxpayer transfer GBP 1,260 of their GBP 12,570 Personal Allowance to a basic-rate spouse or civil partner, saving GBP 1,260 x 20% = GBP 252 a year for 2026/27. HMRC delivers this by adjusting both tax codes. Worked example: Sam earns GBP 8,000 (below the Personal Allowance, so a non-taxpayer) and transfers GBP 1,260 to partner Alex, who earns GBP 35,000. Sam's allowance falls to GBP 11,310, shown as tax code 1131N. Alex's allowance rises to GBP 13,830, shown as 1383M, so GBP 1,260 less of Alex's income is taxed at 20%, saving GBP 252 across the year via PAYE. The 'N' means 'I have transferred allowance away'; the 'M' means 'I have received transferred allowance'. The recipient must be a basic-rate taxpayer (income roughly GBP 12,571 to GBP 50,270 in England, Wales and NI). Once claimed, it renews automatically each year and the codes carry forward, so you do not reapply. If circumstances change, for example the lower earner starts earning above the Personal Allowance or you separate, you should cancel it to avoid a tax bill. Backdating up to four tax years is possible if you were eligible. Use the Marriage Allowance calculator to check the saving, then apply or cancel at gov.uk/marriage-allowance.
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This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.