Simple Interest Calculator
Simple Interest Calculator I = Prt
Enter the principal, interest rate and time. Interest is not added to the principal: I = P × r × t, and the total received is A = P + I.
The calculator above computes simple interest, where interest is always calculated on the original principal only.
Formulas used
I = P · r · t
A = P(1 + r·t)
- P is the principal, r the rate per period as a decimal, and t the number of periods.
- Make sure r and t use the same time unit (both yearly or both monthly).
Worked example
Deposit 10,000 at 6% per year for 3 years:
I = 10,000 · 0.06 · 3 = 1,800, A = 11,800
Enter the same values in the calculator above to see every step of the solution.
How to use the calculator
- Enter the principal, the interest rate per period, and the number of periods.
- Press the calculate button. The result appears instantly.
- Read the step-by-step solution, rendered with KaTeX, to check your own work.