How much interest is owed on a debt?
When a debt is paid late, interest is often added, and working out the simple interest helps you see what is really owed. This calculator works out simple interest on an amount over a period at a rate you set. It is a general calculation tool, not advice on a particular debt or claim.
How it works
Enter the amount, the interest rate, and the period — or the start and end dates — and the calculator works out the simple interest and the total. Simple interest is calculated on the original amount only, not on interest already added.
This is useful in a range of situations: checking the interest element of an unpaid invoice, working out interest claimed on a debt, or sense-checking a figure someone has quoted you. It lets you set the rate yourself, so it is not tied to any one type of claim.
Where a claim involves a statutory rate — such as interest on a late commercial payment, or interest a court may award — the applicable rate is set by the rules rather than chosen. For commercial late payment specifically, our late payment calculator applies the statutory figures.
The result is a calculation based on the figures you enter, not a statement of what is legally recoverable. What interest you can actually claim, and at what rate, depends on the circumstances and may need advice.
Questions about How much interest is owed on a debt?
You can, if you enter the relevant rate. But for business-to-business late payment specifically, the statutory rate and a fixed compensation sum apply, and our late payment calculator works those out automatically.
No. It calculates simple interest on the figures you enter. What interest is actually recoverable, and at what rate, depends on the contract or the law applying to the debt, which may need advice.
Simple interest is the original amount multiplied by the interest rate and the length of the period. The calculator does this for you once you enter the amount, the rate, and either the period or the start and end dates.
Yes. Anything you share is treated in confidence, and nothing you enter into the calculator is stored unless you submit the callback form.
Simple interest is interest calculated only on the original amount, for the whole period, without adding interest onto interest already accrued. It contrasts with compound interest, where each period's interest is added to the balance before the next is calculated.
Simple interest is charged only on the original sum. Compound interest is charged on the original sum plus any interest already added, so it grows faster over time. This tool calculates simple interest.
That depends on your situation. A contract may set a rate, or you may be checking against a rate someone has quoted. Where a statutory or court rate applies, it is fixed by the rules rather than chosen — this tool lets you enter whatever rate is relevant.
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