Emergency tax refund checker (UK)

The problem

Emergency tax codes are non-cumulative - every pay period is treated in isolation, with no catch-up against your year-to-date allowance. This usually means you over-pay PAYE in the periods the emergency code is in force.

The over-payment continues until HMRC issues your employer an updated coding notice (P6) reflecting your real circumstances. The refund typically arrives via payroll on the next pay run after the code is corrected - but only for the current tax year.

Plain-English explanation

Three things drive an emergency-tax over-payment: which emergency code is on your payslip, your pay rate, and how many periods you have spent on the code. The bigger your annual pay, the bigger the per-period over-deduction.

Common scenarios:

• Started a new job without a P45 - payroll defaults you to 0T or BR until HMRC catches up.
• Pension drawdown lump sum - first payment often hit with 0T M1, refund follows once HMRC issues a real code.
• Returning to work after a gap in employment - coding may default to a Week 1 / Month 1 basis.
• Multiple jobs - the second job sits on BR by default; HMRC may need to allocate allowance differently.

For previous tax years, refunds do not flow through payroll. HMRC handles them via their P800 process, or you can claim through your personal tax account.

Worked example - six months on 0T M1

Worked example uses 2026/27 UK figures and is illustrative. Do not use it as a personal tax calculation.

Step by step

1. 1

   Confirm the code is emergency

   Look for M1, W1 or X at the end of your code, or a code of BR or 0T on your only job. Any of these signal a non-cumulative basis.

2. 2

   Estimate the over-payment

   Use the worked example above. Per-period over-deduction × number of periods on the emergency code = the refund estimate for the current tax year.

3. 3

   Update HMRC

   Sign in to your HMRC personal tax account. If you started a new job, confirm your previous job has ended. If you missed a P45, declare your previous earnings via the starter checklist.

4. 4

   Wait for the P6 to reach your employer

   Once HMRC has the right picture, they issue your employer a coding notice (P6). Payroll applies the new code on the next available run and the refund flows through.

5. 5

   For previous tax years, claim via P800

   Refunds for closed tax years are issued by HMRC, not payroll. Check your personal tax account for outstanding P800 calculations.

6. 6

   Run a free PayslipIQ check

   Cross-check the per-period maths and download a Pro Report you can attach to a payroll query if needed.

What to ask payroll

• ?Is my current code on a Month-1 / Week-1 basis or cumulative?
• ?When did you last receive a P6 from HMRC for me?
• ?If HMRC issues a corrected code today, on which pay date will the refund flow through payroll?
• ?Has my P45 from my previous employer been processed?
• ?If I have been on emergency tax across pay rises, will the refund be applied at the new rate or the old?

When to contact HMRC

• Use the gov.uk personal tax account to update your current employment, previous employment and any other income sources.
• For a missing P45, complete the HMRC starter checklist via the tax account so your code can be updated without it.
• Call HMRC PAYE on 0300 200 3300 to request the code be reissued urgently if a payday is approaching.
• For previous tax years, look for a P800 calculation in your personal tax account - that is the route HMRC uses to refund over-paid tax across closed years.

FAQ

How long does an emergency tax refund take?

In the current tax year, once HMRC issues your employer an updated coding notice (P6), the refund typically appears on the next available payroll run - usually within one or two pay periods.

Can I claim an emergency tax refund directly from HMRC?

For previous tax years, yes - via the gov.uk personal tax account or a P800 calculation. For the current tax year, the refund is normally applied through payroll once your code is corrected.

How much emergency tax could I have overpaid?

It depends on which emergency code applied and how many periods it was in force. As a rough guide, 0T or BR on a £42,000 salary over-deducts about £329 per month versus 1257L cumulative.

Do I need a tax refund company to claim back emergency tax?

No. Refunds via your HMRC personal tax account are free. Tax refund companies typically take 25–48% in fees plus VAT for a process you can do yourself in 15 minutes.

Will my employer notify HMRC about the wrong code?

No. Your employer applies whatever code HMRC has issued. You need to update your circumstances directly with HMRC.

Related checkers

• Wrong tax code checker →
• P60 reconciliation checker →
• Overtime tax checker →
• Agency worker payslip checker →