Simple Interest Calculator
Interest computed on the principal only. The I = Prt formula from class, done instantly.
The simple interest formula
I = P × r × t
P is the principal, r the annual rate as a decimal (5% = 0.05) and t the time in years. The total repaid or received is A = P + I. Interest never earns interest, and that is the difference from compound interest.
Where simple interest is actually used
Car loans and most personal loans accrue interest on the outstanding principal (simple interest daily), short-term notes and bonds use it, and it is the standard classroom model. Savings accounts and credit cards compound instead. For those, use the compound interest calculator.