Emergency Tax Calculator UK

Understanding Emergency Tax Codes

Emergency tax is a temporary tax arrangement used by HMRC when they don't have complete information about your tax situation. This commonly happens when you start a new job, return to work after a gap, or work multiple jobs.

Common Emergency Tax Codes

Why You Might Be on Emergency Tax

• Started a new job without providing your P45
• Your previous employer didn't submit your leaving information
• First job and no Starter Checklist completed
• Returning to work after career break or maternity leave
• Working multiple jobs simultaneously
• Coming back to UK after working abroad

How to Use This Emergency Tax Calculator

Our emergency tax calculator helps you work out exactly how much tax you have overpaid and the refund you may be owed. Follow these steps for an accurate result.

Step 1: Enter Your Annual Gross Salary

Input your total annual salary before any deductions. This is the gross figure shown on your employment contract or job offer. If you are paid hourly, multiply your hourly rate by the number of hours you work per week, then multiply by 52 to get your annual equivalent.

Step 2: Select Your Emergency Tax Code

Check your payslip for your current tax code. If you see BR, 0T, D0, D1, or any code ending in W1, M1, or X, you are on emergency tax. Select the matching code from the buttons.

If you are unsure, the most common emergency code for new starters is 0T or BR. You can also select 1257L (the standard correct code) to see what your tax should be for comparison.

Step 3: Specify How Long You Have Been on Emergency Tax

Select the number of months you have been paying emergency tax in the current tax year. The longer you have been on emergency tax, the larger your potential refund will be. Most people are on emergency tax for 1 to 3 months before HMRC corrects the code.

Step 4: Review the Comparison

The calculator displays a side-by-side comparison showing emergency tax paid versus the correct tax amount, along with the potential refund due. The detailed table breaks down gross pay, personal allowance used, tax deducted, and take-home pay for both scenarios.

Understanding Emergency Tax in Detail

Emergency tax is one of the most common payroll issues faced by UK employees. According to HMRC, millions of people are placed on incorrect tax codes each year, often resulting in significant overpayments. Here is a comprehensive guide to how emergency tax works and what you can do about it.

How the UK Tax Code System Works

Your tax code tells your employer how much Personal Allowance to apply before calculating your income tax. The standard code for 2025/26 is 1257L, which means you receive a £12,570 Personal Allowance before any tax is due. The "L" suffix indicates you are entitled to the standard tax-free amount. When HMRC does not have enough information to assign the correct code, they issue an emergency code instead.

The Cumulative vs Non-Cumulative Problem

Under a normal cumulative tax code, your employer calculates your tax based on your total earnings for the year to date, spreading your Personal Allowance evenly across the year. This means if you overpay in one month, the system automatically corrects in subsequent months. Emergency tax codes ending in W1 (week 1) or M1 (month 1) operate on a non-cumulative basis, meaning each pay period is treated in isolation. This prevents any automatic correction and can lead to significant overpayment over time.

How Much Extra Tax Could You Be Paying?

The amount of overpayment depends on your emergency tax code and salary. On the BR code, all your income is taxed at 20% with no Personal Allowance. For someone earning £35,000 per year, the monthly overpayment on a BR code compared to the correct 1257L code is approximately £209.

Over three months, that adds up to roughly £628. On the more severe D0 code (40% on all income), the overpayment would be approximately £1,792 over three months.

2025/26 Tax Rates and Bands Used in This Calculator

This calculator uses the following rates for the 2025/26 tax year, as set by HMRC:

• Personal Allowance: £12,570 (reduced for income over £100,000)
• Basic Rate (20%): £12,571 to £50,270
• Higher Rate (40%): £50,271 to £125,140
• Additional Rate (45%): Over £125,140

Worked Examples: Emergency Tax Overpayments

Example 1: New Starter on BR Code, Earning £30,000

David starts a new job on 1 June but does not provide his P45 from his previous employer. His new employer puts him on the BR tax code. He is on emergency tax for 2 months before HMRC corrects the code.

• Monthly gross pay: £30,000 / 12 = £2,500
• Emergency tax (BR) for 2 months: £2,500 x 20% x 2 = £1,000
• Correct tax (1257L) for 2 months: (£30,000 - £12,570) x 20% / 12 x 2 = £580.50
• Overpayment (refund due): £1,000 - £580.50 = £419.50

Example 2: Higher Earner on 0T Code, Earning £65,000

Priya returns from a career break and starts a new role. She is placed on the 0T code (no Personal Allowance) for 3 months.

• Monthly gross pay: £65,000 / 12 = £5,416.67
• On 0T, her first £4,189/month (basic rate band equivalent) is taxed at 20%, and the remainder at 40%
• Emergency tax for 3 months: approximately £3,013
• Correct tax (1257L) for 3 months: approximately £2,385
• Overpayment: approximately £628

Example 3: Second Job on D0 Code, Earning £25,000

Tom takes a second job alongside his main employment. He earns £25,000 in the second job and is incorrectly placed on the D0 code (all income at 40%) instead of the BR code (20%). He is on the wrong code for 1 month.

• Monthly gross pay: £25,000 / 12 = £2,083.33
• D0 tax for 1 month: £2,083.33 x 40% = £833.33
• Correct BR tax for 1 month: £2,083.33 x 20% = £416.67
• Overpayment: £416.67

How to Get Your Emergency Tax Refund

1. Check Your Payslip
   Look for your tax code. Emergency codes include BR, 0T, D0, or any code ending in W1, M1, or X.
2. Provide Your P45
   Give your P45 from your previous employer to your new employer as soon as possible. This contains your tax code and earnings to date.
3. Complete a Starter Checklist
   If you don't have a P45, complete HMRC's Starter Checklist so your employer can set up your tax correctly.
4. Contact HMRC Directly
   Call 0300 200 3300 or use your Personal Tax Account at gov.uk to update your details and request your correct tax code.
5. Wait for Automatic Refund
   Once your tax code is corrected, your employer will adjust your tax over your remaining pay periods, refunding the overpaid amount.

Frequently Asked Questions

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