Tax overpayments and underpayments
If your tax calculation letter (P800) says you owe tax
HM Revenue and Customs (HMRC) will collect the tax you owe over the next year. This will happen automatically if you:
- pay Income Tax through an employer or pension provider
- earn enough income over your Personal Allowance to cover the underpayment
- owe less than £3,000
HMRC will write to you about how you can pay if they cannot collect the money this way.
If you think your tax calculation is wrong
If you think the amounts used in your calculation are wrong, contact HMRC.
You’ll need to tell HMRC which amounts you think are incorrect and what they should be.
What happens next
If HMRC agrees that your tax calculation was wrong, you’ll be sent a new calculation.
If they disagree, HMRC will contact you to explain why.