Tax Code Checker and Explainer UK 2026
Not sure what your tax code means or whether you're paying the right amount of tax? Our free tax code checker decodes your UK tax code for 2026/27, calculates your tax-free Personal Allowance, and explains exactly what those letters and numbers mean — helping you spot errors that could be costing you hundreds of pounds a year.
Your tax code tells your employer or pension provider how much Income Tax to deduct from your pay. Most people have 1257L for 2026/27, which gives you the full £12,570 Personal Allowance. But if you've recently changed jobs, have multiple incomes, receive benefits, or are on an emergency code, you might be on the wrong tax code — and that means you could be paying too much (or too little) tax.
Getting your tax code right matters. An incorrect code can mean losing £1,000+ per year to overpaid tax, or facing an unexpected tax bill if you've underpaid. Use our checker to verify your code matches your circumstances, then compare your take-home pay with our take-home tax calculator to see exactly how much you should be earning after deductions.
UK Tax Code Essentials 2026/27
- Standard Tax Code: 1257L (Personal Allowance £12,570)
- Scottish Standard Code: S1257L (same allowance, different tax bands)
- Emergency Tax Code: 1257L W1, M1, or X (temporary, often overpays)
- Marriage Allowance Codes: M (receiving) or N (transferring)
- No Allowance Code: 0T (used when allowance used up elsewhere)
- Basic Rate Only: BR (20% on all income from this source)
Check Your Tax Code
How UK Tax Codes Work in 2026
What Is a Tax Code?
Your tax code is a combination of numbers and letters that tells your employer or pension provider how much tax to deduct from your pay under the PAYE (Pay As You Earn) system. The numbers usually represent your Personal Allowance (the amount you can earn tax-free) divided by 10, while the letters indicate specific circumstances like Marriage Allowance, emergency status, or Scottish tax residency.
For 2026/27, the standard Personal Allowance is £12,570, which is why most people have tax code 1257L (12,570 ÷ 10 = 1257, plus L for standard allowance). HMRC calculates your code based on information from your employer, previous tax years, and any benefits or additional income you've declared. If your circumstances change — new job, second income, company car — your code should update automatically, but errors are common.
Understanding the Numbers
The numeric part of your tax code shows how much income you can receive tax-free each year before paying Income Tax:
- 1257 = £12,570 Personal Allowance (standard for most people)
- 1320 = £13,200 allowance (e.g., with Marriage Allowance received)
- 1195 = £11,950 allowance (e.g., reduced by company benefits worth £620)
- 0 = No Personal Allowance (earning over £125,140 or allowance used elsewhere)
Your employer divides this allowance across the tax year, giving you 1/12th of it tax-free each month (for monthly pay). For example, with code 1257L, you get £1,047.50 tax-free each month (£12,570 ÷ 12). Any earnings above this are taxed at 20%, 40%, or 45% depending on your total income.
Decoding the Letters
The letter suffix or prefix shows your specific tax situation:
- L — You're entitled to the standard Personal Allowance (most common)
- M — Marriage Allowance: you've received 10% of your partner's allowance (adds £1,260, so code becomes 1320M)
- N — Marriage Allowance: you've transferred 10% to your partner (reduces your allowance by £1,260, so code becomes 1195N)
- T — Your tax code includes other calculations (complex tax affairs, HMRC needs to review manually)
- 0T — Your Personal Allowance has been used up, or HMRC needs more information (all income taxed, but cumulative basis used)
- BR — Basic Rate (20% tax on all income from this source, usually second job or pension)
- D0 — Higher Rate (40% tax on all income from this source)
- D1 — Additional Rate (45% tax on all income from this source)
- NT — No Tax (you're not paying tax on this income, rare — usually for those under Personal Allowance threshold)
- S (prefix) — Scottish taxpayer (e.g., S1257L uses Scottish tax bands, not UK bands)
- C (prefix) — Welsh taxpayer (e.g., C1257L uses Welsh tax bands)
If you see W1, M1, or X after your code (e.g., 1257L W1), you're on an emergency tax code that taxes you on a non-cumulative basis. This means you don't get credit for unused Personal Allowance from earlier months, often resulting in overpayment. Emergency codes are common when starting a new job without a P45 from your previous employer.
Common Tax Code Scenarios
Here's what different tax codes mean in practice:
- 1257L: Standard code. £12,570 Personal Allowance, one job, no adjustments.
- S1257L: Scottish resident with standard allowance (different tax bands apply: 19%, 20%, 21%, 42%, 45%, 48%).
- 1257L W1 / M1 / X: Emergency code (non-cumulative). You're likely overpaying tax until HMRC updates your details.
- 1320M: You receive Marriage Allowance from your partner (extra £1,260 allowance = £252/year tax saving).
- 1195N: You transfer Marriage Allowance to your partner (reduced allowance by £1,260).
- 747L: Your allowance is reduced (e.g., by £5,100 due to company car or other benefits). £7,470 Personal Allowance remaining.
- BR: Basic Rate code for second job or pension (no Personal Allowance, 20% tax on all earnings).
- 0T: No allowance (earning over £100,000 reduces allowance £1 for every £2 earned; fully removed at £125,140+).
- K codes (e.g., K500): Your deductions (benefits, state pension, tax owed) exceed your allowance. You owe more tax than your allowance covers. K codes increase your taxable income.
If you're comparing job offers and need to understand total take-home pay across different scenarios, use our job offer comparison tool to factor in tax codes and see net income side-by-side.
When Your Tax Code Is Wrong
Your tax code can be incorrect for several reasons:
- Changed jobs without a P45: Emergency code applied, you're overpaying tax.
- Multiple jobs or pensions: Personal Allowance split incorrectly, one source taxed at BR when it shouldn't be.
- Company benefits not updated: You no longer have a company car, but HMRC hasn't adjusted your code (you're overpaying).
- Untaxed income (rental, savings): HMRC estimated too high/low, your code is adjusted incorrectly.
- Marriage Allowance claimed/cancelled: Code not updated after applying or stopping Marriage Allowance transfer.
- High earner (£100k+): Personal Allowance should reduce by £1 for every £2 earned over £100,000, but code not updated correctly.
Consequences of wrong codes:
- Overpaying: You lose money each month. HMRC will eventually refund you (automatically or after you claim), but you miss out on that cash in the meantime.
- Underpaying: You'll receive a tax bill (P800) at the end of the year for unpaid tax. This can be £1,000+ if your code was wrong all year.
Check your tax code every time you: start a new job, get a pay rise, receive benefits, have a second income, turn 65 (different allowances may apply), or move to/from Scotland. If you spot an error, contact HMRC immediately to avoid overpayment or surprise bills.
How to Fix an Incorrect Tax Code
If your tax code is wrong, follow these steps:
- Check online: Log in to your Personal Tax Account on GOV.UK. You can see your current tax code, estimated income, and allowances.
- Update your details: If your employment, pension, or benefits have changed, update these in your Personal Tax Account. HMRC will recalculate your code.
- Contact HMRC: Call the Income Tax helpline on 0300 200 3300 (Monday–Friday, 8am–6pm). Have your National Insurance number, P60, payslips, and details of changes ready.
- Provide evidence: If you've stopped receiving benefits (e.g., no longer have a company car), provide a letter from your employer confirming this.
- Wait for confirmation: HMRC will issue a new tax code (usually within 2 weeks) and send it to you and your employer. Your employer will update payroll from the next pay period.
- Claim refund: If you've overpaid, HMRC will refund you automatically (if under £50) or send a cheque/bank transfer. Check your Personal Tax Account for refund status.
Tip: If you're owed a refund, you can claim up to 4 years back. Don't assume HMRC will find errors automatically — they often rely on you spotting mistakes and reporting them.
This checker helps you understand your tax code, but for full tax calculations including National Insurance, pension, and student loan deductions, use our PAYE tax breakdown calculator to see your complete monthly take-home pay.
Example: Wrong Emergency Tax Code Costs £800/Year
Scenario
James started a new job in April 2026 earning £30,000 per year (£2,500/month). He didn't provide a P45 from his previous employer, so his new employer put him on emergency tax code 1257L M1. This means he's taxed on a non-cumulative basis each month without credit for unused allowance from earlier months.
Tax Comparison
| Correct Code (1257L) | Emergency Code (1257L M1) | |
|---|---|---|
| Personal Allowance (monthly) | £1,047.50 | £1,047.50 |
| Taxable income (monthly) | £1,452.50 | £1,452.50 |
| Tax calculation method | Cumulative (carries forward unused allowance) | Non-cumulative (no carry forward) |
| Income tax (monthly) | £290.50 | £357.50 |
| Overpayment per month | — | £67 |
| Annual overpayment (12 months) | — | £804 |
Key Insights
- James overpays £67 per month (£804 per year) while on the emergency code.
- HMRC should automatically correct this within 6 weeks once they receive his employment details, but this doesn't always happen.
- If James doesn't notice and the code isn't corrected, he'll get a refund eventually (via P800 after the tax year ends), but he loses access to that £804 in the meantime.
- To fix it immediately: James should log in to his Personal Tax Account and update his employment details, or call HMRC on 0300 200 3300.
- If you're on an emergency code and waiting for correction, check your next payslip — if it still shows W1, M1, or X after 6 weeks, chase HMRC.
Use the checker above to verify your tax code is correct. If you're on an emergency code or see unexpected deductions, compare your actual take-home with our take-home tax calculator to spot overpayments.
Frequently Asked Questions
What does tax code 1257L mean?
Tax code 1257L is the most common UK tax code for 2026/27. It means you have the standard Personal Allowance of £12,570 — the amount you can earn each year before paying Income Tax. The number 1257 comes from dividing £12,570 by 10, and the letter L indicates you're entitled to the basic Personal Allowance with no adjustments for Marriage Allowance, benefits, or other income.
Most PAYE employees who have one job and no other taxable income (benefits, rental, dividends) will have code 1257L. Your employer uses this code to calculate how much tax-free income to give you each pay period:
- Monthly pay: £1,047.50 tax-free per month (£12,570 ÷ 12)
- Weekly pay: £241.73 tax-free per week (£12,570 ÷ 52)
Any earnings above your monthly/weekly tax-free amount are taxed at 20% (basic rate) up to £50,270 total income, then 40% (higher rate) up to £125,140, then 45% (additional rate) above that. If you have code 1257L and earn £30,000/year, you pay zero tax on the first £12,570, then 20% on the remaining £17,430 = £3,486 annual Income Tax.
When 1257L is NOT correct: If you have multiple jobs, receive company benefits (car, health insurance), have untaxed income (rental, savings interest over £1,000), or earn over £100,000 (Personal Allowance reduces), your code should be different. Check your code matches your circumstances with our checker above.
How do I know if my tax code is correct?
To check if your tax code is correct, compare it against your current circumstances:
- Single job, standard allowance: Code should be 1257L (or S1257L for Scottish taxpayers, C1257L for Welsh).
- Multiple jobs or pensions: Your main job should have a code with numbers (e.g., 1257L), while secondary incomes should use BR (20% basic rate), D0 (40%), or D1 (45%).
- Company benefits: Numbers should be lower than 1257 (e.g., 1100L if you have a company car worth £570/year benefit).
- Marriage Allowance: Code should end in M (receiving allowance, e.g., 1320M) or N (transferring allowance, e.g., 1195N).
- High earners (£100k+): Personal Allowance reduces by £1 for every £2 earned over £100,000. At £125,140+, you should have code 0T (no allowance).
- Emergency codes: If your code ends in W1, M1, or X (e.g., 1257L W1), you're on a temporary emergency code and likely overpaying. This should only last 6 weeks maximum.
How to verify:
- Check your latest payslip, P60 (end-of-year certificate), or HMRC letter for your current tax code.
- Log in to your Personal Tax Account on GOV.UK to see what HMRC has on file.
- Use our checker above to decode your code and see if it matches your situation.
- If incorrect, update your details in your Personal Tax Account or call HMRC on 0300 200 3300.
Common mistakes: HMRC often gets company benefits wrong (you stopped having a company car but code still reflects it), doesn't update codes after job changes quickly enough, or incorrectly applies Marriage Allowance. Check your code at least once a year and whenever your circumstances change.
What is an emergency tax code?
An emergency tax code (also called a "week 1" or "month 1" basis code) is a temporary tax code used when HMRC doesn't have full information about your income or tax position. In 2026/27, emergency codes look like 1257L W1, 1257L M1, or 1257L X:
- W1 (week 1): For weekly-paid employees
- M1 (month 1): For monthly-paid employees
- X: Alternative notation for emergency status
What makes it different: Emergency codes use non-cumulative tax calculation, meaning:
- You get 1/52nd (W1) or 1/12th (M1) of your annual Personal Allowance each pay period.
- You don't get credit for any unused allowance from earlier months/weeks in the tax year.
- This often results in overpaying tax, especially if you started mid-year or had periods of low/no income.
When emergency codes are used:
- Starting a new job without providing a P45 from your previous employer.
- Switching from self-employment to PAYE employment.
- Receiving your first UK pension.
- HMRC hasn't updated your tax code after you reported a change.
How to fix it: HMRC should automatically correct emergency codes within 6 weeks once they receive your employment details from your employer. However, this doesn't always happen. To speed it up:
- Give your new employer your P45 from your previous job (if you have one).
- If you don't have a P45, complete a Starter Checklist form (your employer will provide this).
- Update your employment details in your Personal Tax Account at GOV.UK.
- If the code doesn't change after 6 weeks, call HMRC on 0300 200 3300.
Any tax you've overpaid will be refunded — either automatically adjusted in future pay once the correct code is applied, or via a P800 tax calculation after the tax year ends (you'll receive a cheque or bank transfer). Don't wait for HMRC to notice — check your payslip each month and chase them if you're still on W1/M1/X after 6 weeks.
What does the suffix letter in my tax code mean?
The letter at the end of your tax code (or sometimes at the start for Scottish/Welsh taxpayers) indicates your specific tax circumstances. Here's what each suffix means:
- L — You're entitled to the standard Personal Allowance (£12,570 for 2026/27). This is the most common suffix for employees and pensioners with straightforward tax affairs.
- M — You've received Marriage Allowance from your spouse or civil partner. They've transferred 10% of their Personal Allowance to you (£1,260), so your allowance increases to £13,830 (code 1383M). You save £252/year in tax.
- N — You've transferred Marriage Allowance to your spouse or civil partner. Your Personal Allowance reduces by £1,260 to £11,310 (code 1131N). Your partner saves £252/year, but you pay £252 more (net neutral for the household if you're a non-taxpayer).
- T — Your tax code includes other calculations to work out your Personal Allowance. This is used when HMRC needs to review your tax manually (complex tax affairs, multiple income sources, pension adjustments). T codes often need annual review.
- 0T — Your Personal Allowance has been used up, or HMRC needs more information about you. All your income is taxed, but on a cumulative basis (you still get higher-rate thresholds). Common for high earners (£100k–£125k) whose allowance is reduced, or people with multiple incomes.
- BR — Basic Rate (20% tax on all income from this source). No Personal Allowance applied. Used for second jobs, pensions, or when your main income already uses your full allowance.
- D0 — Higher Rate (40% tax on all income from this source). Used when you're a higher-rate taxpayer and this income source is additional.
- D1 — Additional Rate (45% tax on all income from this source). Used when you're an additional-rate taxpayer and this income source is additional.
- NT — No Tax deducted. Rare. You don't pay tax on this income (e.g., you're under the Personal Allowance threshold across all incomes, or HMRC has agreed no tax should be deducted for specific reasons).
- S (prefix, e.g., S1257L) — You're a Scottish taxpayer. You use Scottish Income Tax bands (19%, 20%, 21%, 42%, 45%, 48%) instead of UK bands (20%, 40%, 45%). Personal Allowance is the same, but tax bands differ.
- C (prefix, e.g., C1257L) — You're a Welsh taxpayer. You use Welsh Income Tax rates (currently same as UK rates, but Welsh Government can adjust them independently).
K codes (e.g., K500): These are special codes used when your deductions exceed your allowances. For example, if you receive company benefits worth £7,000/year but your Personal Allowance is only £12,570, and HMRC also collects tax owed from a previous year, your total deductions might exceed your allowance. K codes increase your taxable income (the opposite of normal codes which reduce it). The number after K (e.g., K500) is added to your gross pay before calculating tax. K codes are capped to ensure you don't pay more than 50% of your income in tax.
When to check your suffix: Verify your suffix is correct if you've recently: claimed or stopped Marriage Allowance, moved to/from Scotland or Wales, started a second job, begun receiving benefits, or changed pension arrangements. Incorrect suffixes can cost you hundreds in overpaid or underpaid tax.
How do I change my tax code if it's wrong?
If your tax code is incorrect, follow these steps to get it fixed and claim any refund owed:
Step 1: Check Your Current Tax Code
- Find your tax code on your latest payslip, P60 (end-of-year tax summary), pension statement, or letter from HMRC.
- Log in to your Personal Tax Account on GOV.UK to see what tax code HMRC has issued and why.
Step 2: Identify What's Wrong
- Use our checker above to decode your tax code and see if it matches your circumstances.
- Common errors: emergency code (W1/M1/X) not corrected after 6 weeks, company benefits included that you no longer receive, Marriage Allowance not applied/removed, incorrect Personal Allowance for high earners (£100k+).
Step 3: Update Your Information
- Online (fastest): In your Personal Tax Account, go to "Check your Income Tax" → "Update your employment or pension" → Make changes (remove old jobs, add new jobs, update benefit details).
- By phone: Call HMRC Income Tax helpline on 0300 200 3300 (Monday–Friday, 8am–6pm). Have your National Insurance number, P60, latest payslip, and details of changes ready.
- In writing: Write to HMRC at: Income Tax, Pay As You Earn, HM Revenue and Customs, BX9 1AS. Include your National Insurance number and explain what's wrong.
Step 4: Provide Evidence
- If you've stopped receiving benefits (e.g., no longer have company car), get a letter from your employer confirming the end date.
- If you've changed jobs, provide your P45 from the previous employer.
- If you're claiming Marriage Allowance, ensure both you and your partner meet eligibility (one earning under £12,570, the other a basic-rate taxpayer).
Step 5: Wait for HMRC to Issue New Code
- HMRC will review your information and issue a new tax code (usually within 2 weeks).
- You'll receive a "Tax Code Notice" (form P2 or similar) explaining your new code.
- HMRC also sends the new code to your employer, who updates payroll from the next pay period.
Step 6: Claim Your Refund
- If you've overpaid tax due to the wrong code, HMRC will automatically refund you through your payroll once the correct code is applied (you'll see a lower tax deduction or a credit on your next payslip).
- If the tax year has ended, HMRC will send you a P800 tax calculation showing any refund owed. Refunds under £1,000 are paid automatically; larger refunds may require you to claim online.
- You can claim refunds for up to 4 years back if you've been on the wrong code for multiple years.
Tip: Don't assume HMRC will spot errors automatically. They rely on you or your employer reporting changes. Check your tax code at least once a year (ideally after your P60 arrives in May) and whenever your circumstances change (new job, pay rise, benefits change, house move). If you're still unsure after checking, use our PAYE tax breakdown calculator to see what your take-home pay should be with the correct code, then compare it to your actual payslip.
Data Sources & Accuracy
This tax code checker uses official HMRC rates and rules for the 2026/27 UK tax year:
- Personal Allowance: £12,570 (standard for England, Wales, Northern Ireland, and Scotland)
- Income Tax bands (UK): GOV.UK Income Tax Rates 2026/27
- Scottish Income Tax: GOV.UK Scottish Income Tax (different bands: 19%, 20%, 21%, 42%, 45%, 48%)
- Tax codes explained: GOV.UK Tax Codes
- Marriage Allowance: GOV.UK Marriage Allowance (10% transfer = £1,260, saves £252/year)
- Emergency tax codes: GOV.UK Emergency Tax
Disclaimer: This tool provides guidance only and does not constitute tax advice. Tax codes can be complex, especially for those with multiple incomes, company benefits, or high earnings. Always verify your tax code with HMRC and check your Personal Tax Account for the most accurate information. For personalized tax advice, consult a qualified accountant or tax advisor. HMRC helpline: 0300 200 3300.
Your Privacy & Data Security
This tax code checker runs entirely in your browser using JavaScript. No tax code, salary, or personal information is sent to our servers, stored, or shared with third parties. All decoding and calculations are performed locally on your device, ensuring your sensitive tax information remains completely private.
To check your official tax code and make changes, visit your Personal Tax Account on GOV.UK or contact HMRC on 0300 200 3300. For tax advice and refund claims, contact a qualified accountant or use HMRC's free services.