Contractual Interest Calculator
Calculates compound interest based on Bank of England Base Rate plus margin.
About this calculator
This calculator applies contractual interest at the Bank of England Base Rate plus an agreed margin, compounded daily. It applies the correct historical rate for every day of the calculation period automatically, including across multiple rate changes.
It is designed for loans, director’s loan accounts, shareholder agreements and other arrangements where the contract specifies interest at base rate plus a margin. It does not calculate statutory late payment interest on overdue invoices — for that use the Statutory Late Payment Interest Calculator.
This calculator is free to use. Once your calculation is complete, a court-ready PDF report with a full breakdown is available to download for £5.99. Learn how contractual interest is calculated.
This calculator applies contractual interest at the Bank of England Base Rate plus an agreed margin, compounded daily. It applies the correct historical rate for every day of the calculation period automatically, including across multiple rate changes.
It is designed for loans, director’s loan accounts, shareholder agreements and other arrangements where the contract specifies interest at base rate plus a margin. It does not calculate statutory late payment interest on overdue invoices — for that use the Statutory Late Payment Interest Calculator.
This calculator is free to use. Once your calculation is complete, a court-ready PDF report with a full breakdown is available to download for £5.99. Learn how contractual interest is calculated.
Breakdown
| Date | Base + Margin | Interest | Balance |
|---|
Want to understand how contractual interest is calculated? Read our full guide.