About this calculator
The Court Interest Calculator UK estimates simple interest on an unpaid money judgment where judgment interest applies. It is useful for creditors, debtors, small businesses, and advisers who need a planning figure for interest since judgment, including partial-payment scenarios. The calculator is an arithmetic helper only: the judgment order and court rules decide whether interest is actually recoverable.
Judgment interest method
The calculator models simple interest on the outstanding principal balance. It uses an annual rate, converts it to a daily rate, calculates interest for each period, and updates the balance when payments are entered.
- daily rate = annual rate / 365
- period interest = outstanding principal x daily rate x days
- payment allocation = accrued interest first, then principal
- outstanding total = remaining principal + unpaid interest
How to use the court interest calculator
- Enter the judgment amount.
- Enter the date interest should start from.
- Enter the calculation date.
- Confirm the rate or statutory assumption used by the calculator.
- Add partial payments with dates where relevant.
- Review accrued interest, daily interest, and total outstanding.
- Check the result against the judgment order before using it formally.
Worked examples
One year of simple interest
Input: GBP 5,000 judgment for 365 days at 8%
Calculation: GBP 5,000 x 8%
Result: Estimated interest is GBP 400 for the year, if interest applies.
Daily interest estimate
Input: GBP 7,300 outstanding principal at 8%
Calculation: GBP 7,300 x 8% / 365
Result: Daily interest is about GBP 1.60 while that principal remains unpaid.
When court interest needs caution
A court interest calculation is only useful if interest is legally payable. The judgment wording, amount, court, claim type, and payment history can all matter. Some users search for a quick 8% calculation, but the official position should always be checked before adding interest to an enforcement figure.
Interest types are not interchangeable
| Interest type | Typical context | Caution |
|---|---|---|
| Judgment interest | After a money judgment where it applies | Check the order and court rules |
| Pre-judgment interest | Interest claimed before judgment | May depend on claim and court discretion |
| Late commercial payment interest | Business-to-business invoices | Different statutory regime may apply |
Why payment dates matter
A payment changes the amount on which later interest is calculated. The same payment produces a different result if it arrives earlier or later, so payment evidence and dates should be kept with the calculation.
Common mistakes and edge cases
- Do not add interest if the order or rules do not allow it.
- Do not confuse judgment interest with late payment interest on invoices.
- Use the correct start date from the judgment or order.
- Partial payments should be entered on the actual received date.
- The model uses simple interest unless the order says otherwise.
Limitations and cautions
This calculator is general legal information and arithmetic only. It is not legal advice and does not decide whether interest is recoverable.
- Check the court order and current Civil Procedure Rules.
- Use formal legal advice for enforcement or disputed debts.
- Keep evidence of payments and dates.
Frequently asked questions
What rate does the calculator use?
It models the rate entered or the statutory assumption shown by the calculator. Use it only where that rate applies.
Does every CCJ get interest?
No. Whether interest applies depends on the judgment and rules.
Is the interest compounded?
No. The model uses simple interest unless stated otherwise.
How are payments handled?
Payments are used to update the balance from the payment date, so later interest is calculated on the reduced amount.
Can I use this in court paperwork?
Treat it as a checking figure. Formal paperwork should match the order, rules, and payment evidence.
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