tax and allowances A few digits and a letter decide how much tax comes off a workplace pension each month. In retirement that code is doing more work than it does during a working life, because it is usually carrying the tax on a State Pension that is never taxed directly. Knowing how to read it is the difference between spotting an error and living with one.
A tax code is an instruction from HM Revenue & Customs to whoever pays you. It tells them how much of your income from that source to treat as tax-free, and everything above it is taxed.
During working life the code usually sits at the standard figure and nobody looks at it twice. In retirement it often does not, and the reason is almost always the State Pension.
The number is an amount, divided by ten
The number in a tax code is the tax-free amount for that source, with the last digit removed.
1257L — the most common code in the UK — means £12,570 of tax-free income, which is the standard Personal Allowance. The letter describes the circumstances rather than the amount.
What the letters mean
| Code | What it means |
|---|---|
| L | Entitled to the standard tax-free Personal Allowance. |
| M | Has received a Marriage Allowance transfer from a spouse or civil partner. |
| N | Has transferred part of the allowance to a spouse or civil partner. |
| BR | All income from this source taxed at the basic rate, with no allowance applied. |
| D0 / D1 | All income from this source taxed at the higher rate, or the additional rate. |
| 0T | No Personal Allowance applied to this source, often because HMRC lacks details. |
| K | Deductions exceed the allowance. The number is added to taxable income rather than subtracted. |
| NT | No tax is to be deducted from this source. |
A BR code on a second pension is normal rather than wrong: the allowance has already been given against the first source, so the second is taxed in full from the first pound.
Why a retirement code looks so small
Because the State Pension is paid without tax deducted, HMRC recovers the tax due on it by reducing the tax-free amount given against another source. The State Pension is entered as a deduction in the coding calculation.
With the full new State Pension at £12,547.60 a year and the Personal Allowance at £12,570, almost the entire allowance is used up by the State Pension alone.
| Step | Amount |
|---|---|
| Personal Allowance | £12,570.00 |
| Less State Pension | −£12,547.60 |
| Tax-free amount left for the workplace pension | £22.40 |
| Resulting tax code | about 2L |
A code of 2L on a workplace pension looks alarming, and it is the single most common cause of "my tax code has collapsed" enquiries among pensioners. It is not a mistake. It reflects a State Pension that has consumed virtually the whole allowance. The underlying position is explained in why a bigger pension can still mean a tax bill.
about K codesWhere the State Pension and other deductions exceed the Personal Allowance altogether, HMRC issues a K code. The number is added to taxable income rather than taken away, so more tax comes off the other pension. There is a protection: no more than half the gross payment from a source can be taken as tax under a K code.
Why a code changes in April
New codes are issued before the start of each tax year, and the April uprating feeds into them. If the State Pension rises while the Personal Allowance stays frozen, the deduction grows and the code falls.
A code can also change mid-year — when a new pension starts, when Marriage Allowance is claimed, or when HMRC collects an underpayment from an earlier year through the code.
The estimate problem
HMRC codes against an estimate of the State Pension for the year, usually calculated by annualising the weekly rate. The actual amount paid in a tax year can differ slightly, because payment cycles do not align neatly with the tax year and the April rate change falls mid-cycle — the issue covered in the four-weekly cycle that makes a pension look wrong.
The result is usually a small under- or overpayment, reconciled after the year ends through a P800 calculation or Simple Assessment. Small differences are normal. Large ones are worth querying.
When a code really is wrong
Worth checking if any of these apply:
- The State Pension figure on the coding notice does not match the award letter.
- A pension that ended years ago still appears as a live source.
- A BR or 0T code sits on the only source of income.
- An emergency code — marked W1, M1 or X — is still in place months after a pension started. These tax each payment in isolation and frequently over-deduct.
- Marriage Allowance was claimed but no M or N appears.
- An S or C prefix does not match where you live.
How to get it corrected
Codes are changed by HMRC, not by the pension provider — the provider only applies what it is sent. The quickest route is the personal tax account on GOV.UK, where the figures behind the code are shown and estimated income can be updated directly. HMRC also has a telephone line for income tax enquiries.
When a code is corrected during the tax year, the adjustment normally works through automatically and any over-deduction comes back in a later payment rather than as a separate refund.
The point worth taking away
In retirement the tax code on a workplace pension is rarely about that pension. It is where the tax on an untaxed State Pension is collected, which is why the number is so much smaller than people expect. Read the coding notice rather than the code alone: the deduction lines show exactly what HMRC has assumed, and that is where an error, if there is one, will be visible.
sources
General information. This article is sponsored content published by Riescola Pres, a service of Exigon Consulting OÜ. It explains published public rules and figures and is not personal financial, tax or legal advice. Riescola Pres is independent of, and not endorsed by, GOV.UK, the Department for Work and Pensions or HM Revenue & Customs, and no application can be made through this website. Any amounts shown are the official published rates for the stated period or clearly labelled worked examples; what an individual receives depends on their own record and circumstances. Figures correct as at 15 October 2026.
the weekly bulletin The week's pension and retirement reporting, in one email.
One email a week on the State Pension, tax in retirement and the support that pensioners can apply for. Free to receive, and you can unsubscribe from any edition.
Double opt-in. Your address is used for this newsletter and is not passed to third parties.
tax and allowances
state pension