Check for Overpaid PAYE Tax
Frequently Asked Questions
What are emergency tax codes and how do they cause overpayment?
Emergency tax codes include BR (all income taxed at basic rate 20%, no personal allowance), 0T (no personal allowance, tax at 20%/40%/45% on each band), and W1/M1 suffixes (non-cumulative — each pay period treated independently). These can result in significant overpayments, especially if you start a new job, take a pension, or change employment mid-year.
How will HMRC notify me if I've overpaid tax?
After the tax year ends (5 April), HMRC reconciles PAYE records and issues a P800 tax calculation if you have overpaid. This is usually sent between June and November. Some taxpayers also receive a Simple Assessment (PA302). If you do not receive one by November you can contact HMRC directly.
Can I reclaim tax overpaid during the current tax year?
Yes, if you are no longer working (e.g. you have left a job or retired) you can claim a refund in-year using form P50. If you have taken a pension lump sum and overpaid due to emergency tax, use form P55 (partial drawdown) or P53Z (full withdrawal).
What is a cumulative vs non-cumulative (W1/M1) tax code?
A cumulative tax code takes into account all income and tax paid since the start of the tax year, ensuring the right amount is deducted overall. A non-cumulative (Week 1/Month 1) code treats each pay period in isolation, ignoring any unused personal allowance from earlier in the year — often leading to overpayment.
How do I update my tax code to prevent future overpayments?
You can update your tax code via your Personal Tax Account at GOV.UK, by contacting HMRC on 0300 200 3300, or by checking that your employer has submitted an accurate starter checklist. HMRC will also update your code automatically when it reconciles your records.