UK Emergency Tax Calculator
Estimate your emergency tax for this pay period and compare it with a standard PAYE estimate.
What is emergency tax?
Emergency tax is a temporary tax deduction used when HMRC or your payroll team does not yet have complete information about your tax position. This often happens when you start a new job, switch employers, return to work after a break, or begin receiving taxable benefits.
The key issue is that emergency tax can over-deduct in the short term, which can make your payslip feel wrong. The good news is that overpayments are usually corrected once your tax code is updated.
Common emergency tax codes
- 1257L M1/W1: Personal allowance is applied on a non-cumulative basis (month-by-month or week-by-week).
- 0T M1/W1: No personal allowance is applied for the period.
- BR: Income is taxed at basic rate (20%).
- D0: Income is taxed at higher rate (40%).
- D1: Income is taxed at additional rate (45%).
How this emergency tax calculator works
This calculator estimates your tax for one pay period using the emergency treatment you select. It also shows a comparison against a standard PAYE estimate based on your expected annual income and a normal personal allowance approach.
This is useful for quickly checking whether you may be overpaying tax right now, and roughly how much that temporary difference could be.
Assumptions in this tool
- Uses 2025/26 style UK income tax bands for England, Wales, and Northern Ireland.
- Compares your emergency result against a simplified standard PAYE estimate.
- Does not include National Insurance, pension contributions, student loan, salary sacrifice, or benefits-in-kind.
Why emergency tax can happen
- You started a new job without a P45.
- Your employer did not yet receive updated tax code details from HMRC.
- You moved from self-employment to payroll employment.
- You have multiple jobs and payroll applies a temporary code.
- You recently changed from part-time to full-time work (or vice versa).
How to fix emergency tax quickly
- Check your payslip for the tax code currently in use.
- Give your employer your latest P45, if available.
- Update your details using your HMRC personal tax account.
- Contact HMRC if your code looks incorrect for your situation.
- Watch future payslips for correction or a refund through payroll.
Can you reclaim emergency tax?
Yes. In many cases, the refund is made automatically through payroll once your code is corrected. If not, you can usually reclaim through HMRC directly, either during the tax year or after year-end depending on your circumstances.
FAQ
Does this include National Insurance?
No. This emergency tax calculator focuses on income tax only.
Is this calculator suitable for Scottish tax bands?
Not exactly. Scotland has different income tax bands and rates, so this is best used as a directional estimate for non-Scottish bands.
What if my annual income varies?
Use your best expected annual estimate and re-run the calculator when your forecast changes. The comparison amount is only as good as that annual estimate.