Tax codes one by one
M and N tax codes
Two letters for one claim: the partner who receives the allowance gets M, the partner who gives it gets N.
1383M takes less over the year
£252.00
| 1257L | 1383M | |
|---|---|---|
| Tax-free amount | £12,570 | £13,830 |
| Tax, first month | £290.20 | £269.20 |
| Tax over the year | £3,484.00 | £3,232.00 |
| Take-home after tax | £26,516 | £26,768 |
Same pay every month, HMRC’s cumulative method, Income Tax only (no National Insurance).
The letters M and N appear when a married couple or civil partners use Marriage Allowance. The lower earner transfers £1,260 of their Personal Allowance to the partner. The partner who receives it gets an M code: £12,570 plus £1,260 gives £13,830, written 1383M. The partner who gives it gets an N code: £11,310 left, written 1131N. The receiving partner's tax falls by up to £252 in 2026 to 2027; on a salary of £30,000, 1383M takes £3,232.00 over the year against £3,484.00 with 1257L. To qualify, the lower earner must normally have income below the Personal Allowance and the partner must pay tax at no more than the basic rate, which usually means income up to £50,270, or up to £43,662 in Scotland, where the intermediate rate is allowed. A claim can be backdated to 6 April 2022 for each year you were eligible, and the transfer then renews automatically each year until it is cancelled.
Marriage Allowance: codes and saving
Couple saves
£252.00
| Codes | 1131N and 1383M |
| Amount transferred | £1,260 |
| Partner’s income limit | £50,270 |
The lower earner must earn under the Personal Allowance, the partner pay tax at the basic rate at most (intermediate in Scotland).
Rules read on HMRC’s texts by Radif Partners · Editorial policy · Method
The two codes side by side
The number in each code is simply the new allowance with its last digit dropped. GOV.UK's table of letters defines M as part of your partner's Personal Allowance received under Marriage Allowance, and N as part of yours transferred to your partner. In the employer guidance, both letters are taxed at the normal rates on whatever pay is left after the allowance, exactly as an L code would be.
| Where you live | Code of the partner who receives | Code of the partner who transfers |
|---|---|---|
| England and Northern Ireland | 1383M | 1131N |
| Scotland | S1383M | S1131N |
| Wales | C1383M | C1131N |
If either partner has company benefits, job expenses or a State Pension in the code, the numbers move away from 1383 and 1131, but the letters stay: whatever the number, an M or an N shows that a transfer is in place.
What the M code saves
For the receiving partner, the extra £1,260 of allowance removes basic rate tax on that slice of income, worth £252 over a full year. On the payslip, the monthly free pay rises from £1,048.26 to £1,153.26.
| Receiving partner, yearly pay | Tax with 1257L | Tax with 1383M | Saving |
|---|---|---|---|
| £20,000 | £1,484.00 | £1,232.00 | £252.00 |
| £30,000 | £3,484.00 | £3,232.00 | £252.00 |
| £45,000 | £6,484.00 | £6,232.00 | £252.00 |
The full saving needs income above £13,830, so that the whole extra allowance is used. Below that, the M code still cuts the tax, but by less.
Who can claim
All of these must apply, according to GOV.UK:
- you are married or in a civil partnership; living together is not enough;
- the lower earner pays no Income Tax, or has income below the Personal Allowance, usually £12,570;
- the other partner pays tax at the basic rate, usually income between £12,571 and £50,270 before the transfer; in Scotland the starter, basic or intermediate rate, usually up to £43,662.
Receiving a pension or living abroad does not prevent a claim, provided you receive a Personal Allowance. If either of you was born before 6 April 1935, Married Couple's Allowance may be worth more, and the two cannot be held together. Once HMRC accepts the claim, the new allowances are backdated to 6 April of the current year, and the cumulative payroll returns the extra tax through the next payslips.
Two codes on the same pay
1383M against 1257L, over the year
−£252.00
| Tax with 1257L | £3,484.00 |
| Tax with 1383M | £3,232.00 |
| Each month | £21.00 |
Keeping the codes right
The transfer renews each April until someone cancels it, so the M and N should reappear every year. Check both codes in your HMRC online account when a new year starts or after a change of job. If the lower earner's income rises above the allowance, or the receiving partner moves into the higher rate band, the claim should be cancelled; the person who made the claim does that, unless the relationship has ended. If you complete a Self Assessment return, you do not need to fill in its Marriage Allowance section while your codes already end in M or N.
A bereavement changes the codes in a specific way. If the partner who received the allowance dies, their estate is treated as having the larger allowance and yours returns to the normal £12,570, so your N code goes back to an ordinary one. If the partner who transferred the allowance dies, your larger allowance of £13,830 stays until 5 April and the M remains on your code until then. If your partner died after 5 April 2022, a claim is still possible by phoning HMRC's Income Tax helpline.