Brief delay on a modest tax amount
A company clears a smaller Corporation Tax balance soon after the due date.
The estimated interest remains limited because both the amount and the delay are contained.
Practical compliance tool
Corporation Tax Interest Calculator
Estimate late-payment interest on Corporation Tax using the tax due, the delay period, and the annual interest rate you want to apply.
Interest can continue to grow even when the penalty question feels manageable, so this tool isolates the time-cost of the delay.
Corporation Tax Interest Calculator
Estimate late-payment interest on Corporation Tax using the tax due, the delay period, and the annual interest rate you want to apply.
What this interest result gives you
The result turns the payment delay and annual rate into an estimated interest figure for the Corporation Tax amount due.
It is intended for planning and triage, not as a substitute for HMRC’s own formal calculation on a live account.
Rule summary
Late-payment interest is time-based
Interest grows with both the amount outstanding and the number of days the tax remains unpaid.
Even where the penalty position is separately manageable, the interest cost can keep accumulating until the liability is cleared.
Worked examples
How the result behaves in practice
Longer delay on a larger balance
A larger tax debt stays unpaid for a more material period.
The calculator shows how the interest grows even before wider recovery action is considered.
Turn the result into an action plan
Use the payment deadline tool if you still need to confirm the correct starting date.
Pair the result with the late-payment penalty estimate so the cash impact is viewed together.
If the amount is material, build the date and payment plan into the compliance calendar rather than leaving it as a one-off estimate.
Read the guide
Corporation Tax interest rules
Use this guide to understand late-payment interest on Corporation Tax and why it keeps growing while the debt remains unpaid.
Assumptions and limits
This tool gives a practical estimate and depends on the assumptions shown below.
Assumptions
- The inputs entered are complete and reflect the facts for the relevant filing, tax, or compliance period.
- The tool is used for a standard scenario rather than a specialist exception, relief, or disputed case.
Limits and rule basis
- This tool does not replace detailed professional review where the facts are unusual or contested.
- If the underlying rule depends on reliefs, appeals, or special handling, the real outcome may differ.