Simple interest is calculated primarily on the original principal for the agreed period, while compound interest involves interest being calculated on the principal plus previously accumulated interest. The way interest is calculated can therefore produce very different results over time.
Simple interest is common in certain loan and financial calculations, while compound interest is widely used for savings, investments, and some other financial products. The exact calculation method depends on the specific product and agreement.
For borrowers, it’s important to understand how interest is actually calculated rather than assuming every loan uses the same method. Some installment loans use an amortization structure where each payment covers both interest and principal, so the balance changes throughout the repayment period.
If you’re comparing interest concepts or want to see how compounding changes a balance over time, our simple interest calculator and compound interest calculator can help illustrate the difference.
