Interest clauses in loans serve the fundamental purpose of offering a return to a lender on the capital they make available to a borrower.
They also serve a secondary purpose of compensating for the opportunity cost associated with delayed payments to the extent that a borrower defaults.
Myerson Solicitors' banking lawyers discuss interest calculation, the enforceability of interest, and the case of Houssein v London Credit [2023].
How do you calculate interest?
Interest can be calculated in a number of ways, including one or a combination of the following:
- Simple interest - calculated solely on the principal amount over a specific period at a fixed rate.
- Compound interest – calculated on both the initial principal loan and the accumulated interest over time, resulting in interest being charged on interest.
- Variable - calculated by reference a specified rate, such as the Bank of England base rate or SONIA (Sterling Overnight Index Average), plus a margin.
Default interest, on the other hand, is an additional rate applied over and above the standard interest rate, charged when a borrower fails to meet their payment obligations, incentivising timely repayments and compensating lenders for the increased risk.
It serves as a deterrent against defaulting on loans or debts, as well as providing a mechanism for creditors to recoup losses.