The 1131L tax code means HMRC has set your tax-free personal allowance at £11,310 for the year, which is £1,260 less than the standard £12,570 allowance that comes with code 1257L. The “L” confirms you still qualify for the standard personal allowance in principle; the lower number tells you HMRC is collecting extra tax through your wages to account for something else, usually a company benefit, untaxed income, or tax you underpaid in a previous year.1GOV.UK. What Your Tax Code Means
What the Number and Letter Actually Mean
Every PAYE tax code has two parts. The number multiplied by 10 is your annual tax-free allowance, so 1131 means £11,310 of your pay each year comes to you before income tax applies. The letter tells your employer which category of allowance you fall into, and “L” is the standard suffix for someone entitled to the normal personal allowance.1GOV.UK. What Your Tax Code Means
HMRC calculates your code and sends it to your employer electronically. Your employer applies it but doesn’t set it. On a monthly payslip, a 1131L code gives you roughly £942.50 of tax-free pay each month, compared with about £1,047.50 under 1257L. You don’t owe the difference as a single sum; the extra tax is spread evenly across every pay period.
Why Your Allowance Is £1,260 Lower Than Standard
HMRC starts with your full personal allowance and subtracts the value of anything else that needs taxing through PAYE.1GOV.UK. What Your Tax Code Means A £1,260 reduction most often reflects one of the following:
- A taxable company benefit such as a company car, private medical insurance, or another benefit in kind, where HMRC estimates the annual value and collects the tax through your pay.
- Untaxed income such as savings interest above your Personal Savings Allowance, or casual earnings, built into the code so you don’t have to pay separately.
- Tax underpaid in a previous year, which HMRC recovers by shrinking this year’s allowance rather than sending a bill.
- State Pension income, which is paid without tax deducted; if you also have a job, HMRC reduces your employment code to collect the tax on the pension.
- The High Income Child Benefit Charge, which applies to parents earning over £60,000 who receive Child Benefit and can be collected through PAYE.
Your Notice of Coding (form P2) shows exactly which of these is behind your specific £1,260 reduction, item by item.2GOV.UK. How They Are Used and Calculated – P2 Notice of Coding
What 1131L Is Not
Transferring Marriage Allowance to a spouse or civil partner also reduces your allowance by £1,260, but the resulting code ends in “N,” not “L.”3GOV.UK. Marriage Allowance – How It Works So if your code is 1131L specifically, Marriage Allowance is not the cause. The reason lies elsewhere on your P2.
How Much 1131L Costs You
The £1,260 of allowance you’ve lost becomes taxable income instead. For someone paying the basic rate of 20%, that’s an extra £252 of tax over the year, or roughly £21 a month.
Above the £11,310 threshold, the standard income tax rates for 2025/26 in England, Wales, and Northern Ireland apply:
- Basic rate of 20% on income from £11,311 to £50,270
- Higher rate of 40% on income from £50,271 to £125,140
- Additional rate of 45% on income above £125,140
Scotland uses a different band structure with six rates ranging from 19% to 48%, so Scottish taxpayers on 1131L will see slightly different deductions from the same gross pay.4GOV.UK. Income Tax Rates and Personal Allowances
How to Check Why HMRC Gave You This Code
Start with your P2. HMRC issues one whenever your code changes, and it breaks the calculation down line by line: your starting allowance, each deduction, and the tax-free figure that results.2GOV.UK. How They Are Used and Calculated – P2 Notice of Coding The item worth £1,260 will be listed there.
If you don’t have your P2, sign in to the “Check your Income Tax” service on GOV.UK. It shows your current code, how it was calculated, and the employment, pension, and benefits information HMRC holds about you.5GOV.UK. Check Your Income Tax for the Current Year Look for anything outdated: a company car you handed back, a benefit that ended, a second income you no longer receive.
Your P60 at the end of the year, or a P45 if you leave a job partway through, confirms the total pay and tax deducted so you can check the code was applied correctly across your payslips.6GOV.UK. Your P45, P60 and P11D Form
Getting the Code Corrected
If the information HMRC is working from is wrong, update it through the “Check your Income Tax” service. You can correct benefits, income, and employment details online, and HMRC will recalculate your code from there.7GOV.UK. If You Think Your Tax Code Is Wrong
If you can’t use the online service, call the HMRC income tax helpline. One caveat if you’ve just started a new job: wait 35 days before contacting HMRC, because your code often corrects itself once your new employer’s details reach them.7GOV.UK. If You Think Your Tax Code Is Wrong
Once HMRC accepts the change, they’ll notify you and your employer within 15 working days. Monthly-paid workers should see the new code on the next payslip or the one after; weekly-paid workers should see it by the third payslip. If it doesn’t appear, ask your employer’s payroll team whether they’ve received the updated code.7GOV.UK. If You Think Your Tax Code Is Wrong
Reclaiming Tax You’ve Already Overpaid
Fixing the code stops the overcharging going forward, but it doesn’t automatically refund what you’ve already paid. After the tax year ends, HMRC reconciles PAYE records and sends a P800 calculation letter between June and the following March if you’re owed a refund or have underpaid.8GOV.UK. Tax Overpayments and Underpayments
If you’re confident you’ve overpaid and don’t want to wait, you can claim through your personal tax account or by contacting HMRC directly. The automatic reconciliation is reliable in straightforward cases, but a wrong code that was only in place for part of the year may not produce a clean refund without you flagging it.