Interest: Interest start and end dates
You must check whether, and from which date, the FA 2009 interest rules apply to the tax or duty you are dealing with. See CH140160 for full details.
We calculate interest from the interest start date to the interest end date. There is more detailed guidance at
This page defines the various interest start and end dates that we refer to in this guidance.
CH140220 explains how to calculate the number of days from the start date to the end date.
Note that there are definitions of other terms in the glossary at CH149950.
Late payment interest start date
The late payment interest start date in respect of any amount is the date on which that amount becomes due and payable, even if the start date is a non-business day within the meaning of section 92 of the Bills of Exchange Act 1882.
There are also special provisions that apply in particular circumstances that change the late payment interest start date, see CH143000+.
Late payment interest end date
Late payment interest runs to the late payment interest end date.
For late payment interest, the end date is the date on which payment is made or set-off takes place, see CH140200.
Repayment interest start date
Repayment interest runs from the repayment interest start date until the date on which HMRC makes payment.
The ‘repayment interest start date’ depends on whether the amount was originally paid to HMRC or whether it arose because of a return or claim.
- For repayment of amounts paid to HMRC, the repayment interest start date is the later of
* the date when the amount was paid to HMRC, and * the date the repayment became due and payable to HMRC.
- For situations where payment of amounts becoming overpaid or a repayment becomes due because of a return or claim, the repayment interest start date is the later of
* the date when the return was required to be filed, or the claim to be made, and * the date when the return was actually filed or the claim actually made.
You won’t use this second definition of the repayment interest start date yet because it is not relevant to the taxes to which the FA 2009 interest provisions currently apply, see CH140160.
Repayment interest is paid even when the start date is a non-business day within the meaning of section 92 of the Bills of Exchange Act 1882.
There are also special provisions that apply in particular circumstances that change the repayment interest start date, see CH146220+.
Repayment interest end date
Repayment interest runs to the end date.
For repayment interest the end date is the date when the amount is
- repaid to the person, or
- paid to another person, or
- set off against that, or another, person’s liability.