What does the tax code
1255L mean?
1255L means a £20 cut to your allowance. Small deductions like this are frequently untaxed savings interest being collected through PAYE rather than anything to do with your job.
Check if 1255L is right for you
Free and instant, no sign-up. HMRC rates for 2026/27, or every year you can still claim.
Add your benefits, pension and Marriage Allowance for a sharper answer.
Get the detailed breakdown + free reclaim guideThere is a particular moment that produces codes like 1255L: interest rates rise, a savings account that used to earn very little starts earning something, and a deduction appears in a tax code belonging to someone who has never thought of themselves as having investment income. Your allowance for 2026/27 becomes £12,550 rather than £12,570, and nothing about your job has changed at all.
- 1255L Tax Code
- An ordinary L-suffix code giving £12,550 of tax-free pay for 2026/27, £20 below the standard allowance. Small deductions of this size commonly represent tax on income that has no PAYE of its own, such as savings interest above your Personal Savings Allowance, being collected through your wages instead.
How savings interest ends up in a tax code
Banks and building societies pay interest without deducting tax and report what they paid to HMRC. HMRC then decides whether any tax is due, and if it is, the usual way to collect it from an employee is to shrink their tax code rather than send a bill.
The Personal Savings Allowance decides how much interest escapes tax entirely:
| Your tax band | Personal Savings Allowance |
|---|---|
| Basic rate (20%) | £1,000 |
| Higher rate (40%) | £500 |
| Additional rate (45%) | £0 |
Interest inside the allowance is tax free and produces no deduction. Interest above it is taxable, and that is what lands in your code. Interest inside an ISA never counts at all, whatever the amount.
Note the cliff edge at the top of the basic rate band. Moving from basic to higher rate halves your savings allowance from £1,000 to £500 at the same moment your marginal rate rises, so a modest pay rise can produce a coding deduction that looks disproportionate to it.
Why the deduction is not the same as the interest
This trips people up constantly. If HMRC thinks you will receive £20 of taxable interest, it reduces your allowance by £20, and you then pay tax on that £20 at your normal rate. The deduction equals the income, not the tax on it.
So a £20 deduction is collecting £4 from a basic rate taxpayer. If you have received a coding notice showing a £20 reduction and assumed HMRC wanted £20 from you, the real figure is a fifth of that.
The arithmetic runs the other way for deductions that recover an underpayment, which is a different mechanism entirely and covered on our 1231L page.
Worked example: 1255L on a £26,000 salary
- Gross salary: £26,000
- Subtract the 1255L allowance: £26,000 minus £12,550 = £13,450 of taxable income
- Taxed at 20% within the basic rate band
- Income tax for the year: £2,690
- Monthly tax-free pay: £12,550 divided by 12 = £1,045.83
On the standard 1257L code the same salary gives £13,430 taxable and £2,686 of tax. The difference is £4 across twelve months, about 33 pence a month. Income tax only, National Insurance excluded, and an estimate to confirm with HMRC.
The reason small savings deductions are so often wrong
Everything in this part of a tax code is a forecast, and forecasts about interest age badly.
HMRC is projecting forwards from an old figure. The deduction in your 2026/27 code is typically based on interest reported for an earlier year. If you spent the savings, moved them into an ISA, or the rate on the account fell, the projection is now describing money you are not receiving.
Rate changes move the number without you doing anything. A fixed balance earning a variable rate produces different interest every year, so a deduction that was right once drifts out of accuracy on its own.
A joint account can be counted twice. Interest on a joint account is normally split between the holders. If both codes carry the full amount, both people are paying tax on income that only one of them received.
The band boundary matters more than the balance. Someone who tipped into higher rate had their savings allowance cut in half. The interest did not change; the allowance did.
Because the sums are small, almost nobody checks. That is exactly why stale savings deductions can sit in a code for years.
The other income that gets coded out the same way
Savings interest is the most common candidate for a deduction this size, but it is not the only one. PAYE is used as a general purpose collection mechanism for income that has no tax deducted at source, so several quite different things arrive in a code looking identical.
Dividends. Company dividends are paid gross and have their own allowance, above which tax is due at dividend rates. Small holdings often produce deductions in exactly this range.
Rental profit. Income from a property is usually settled through Self Assessment, but modest amounts can be collected through a code instead.
Taxable state benefits. Some benefits are taxable and paid without deduction, so the tax is recovered from your wages. Jobseeker's Allowance and Carer's Allowance are the ones people meet most often, and they surprise almost everybody.
Tips and commission reported separately. Where these are not run through your employer's payroll, they can be coded instead.
The reason this matters is that the fix differs by cause. A savings estimate is corrected by giving HMRC the real figure. A benefits deduction is usually correct and should be left alone. A rental deduction may mean HMRC expects a tax return from you. Reading the label on the deduction line is therefore not optional detail, it is the whole diagnosis.
Whatever the source, the arithmetic is the same: the deduction is the income being brought into charge, and the cost to you is the tax on it.
Is it worth fixing £4?
On its own, no. As a signal, often yes.
A £20 deduction tells you HMRC believes you have untaxed income. That belief will be carried forward and revised, and the revisions are not always downwards. If your savings have grown, next year's deduction may be materially larger, and it is easier to correct an estimate before it compounds than after.
Two situations do justify acting immediately:
- You have no taxable interest at all, because everything is in ISAs or your interest is comfortably inside the Personal Savings Allowance. Then the deduction is simply wrong.
- The deduction has grown year on year without your savings growing. That is a projection running away from reality.
How to correct it
Sign in to your Personal Tax Account at gov.uk/personal-tax-account and open "Check your Income Tax". The breakdown behind your code shows untaxed interest as its own line, with a figure in pounds. You can tell HMRC the correct expected amount there.
Have the real numbers ready: which accounts, what interest each actually paid last year, and which of them are ISAs. A specific correction is accepted far more readily than a general objection.
If the position is more complicated, the Income Tax helpline is 0300 200 3300. Our guide to checking your tax code covers where to find each figure, and the T tax code page explains what happens when HMRC flags your record for review rather than settling on a number.
For an estimate of what your code should be without the deduction, use our free tax code checker. It gives you a figure to take to HMRC, not advice.
People also ask
- 1255L gives £12,550 of tax-free pay in 2026/27, £20 below the standard code
- Small deductions like this are often savings interest above the Personal Savings Allowance, collected through PAYE
- The Personal Savings Allowance is £1,000 at the basic rate, £500 at the higher rate and nil at the additional rate
- The deduction equals the income being taxed, not the tax itself, so £20 costs a basic rate taxpayer £4
- ISA interest never counts, and joint account interest should be split between the holders
- These deductions are projections from earlier years and go stale quickly when rates or balances change
- The £4 is not worth chasing, but the estimate behind it is worth correcting before it grows
Related tax codes: 1256L tax code | 1254L tax code | 1253L tax code | 1257L tax code | T tax code
Stop calculating manually.
TapTax connects to your bank, categorises expenses automatically, and submits quarterly updates to HMRC. Free plan, no card required.