Simple Interest Calculator
Calculate simple interest (I = P·r·t) and the final balance on a principal, where interest accrues only on the original amount.
- Interest earned
- $150.00
- Final balance
- $1,150.00
How it works
Simple interest is I = P × r × t, where P is the principal, r is the annual rate as a decimal, and t is the term in years. The final balance is just P + I. Interest is always calculated on the original principal only — it never compounds on previously earned interest, which is what makes it 'simple' compared to compound interest.