Simple Interest Calculator
Estimate interest that is calculated on the original principal only.
Currency formatting only. Enter your own rate and term; no conversion is applied.
Simple interest inputs
This method does not add previously earned interest to the principal.
Balance over time
Ending balance share
Annual schedule
| Year | Interest | Ending balance |
|---|
Detailed Breakdown
Formula
Simple interest is I = P * r * t, where
P is principal, r is annual rate as a
decimal, and t is time in years. Ending balance is
P + I.
Interpret the schedule
Interest accrues at the same amount each year because it is always based on the original principal. Partial-year terms are prorated by the year fraction.
Limits
This is not an amortized payment schedule and does not model compound interest, fees, payment timing, or local lender conventions.
Simple or compound?
Many deposit accounts and loans compound interest. Check the product terms before using this simple-interest estimate.
Examples
For 20,000 at 3% simple annual interest over 10 years, interest is 6,000 and the ending balance is 26,000, before fees or taxes.
FAQ
Does simple interest earn interest on prior interest?
No. It applies the entered rate to the original principal. Compounding interest on accumulated balance is a different method.
Can I enter part of a year?
Yes, use a fractional year such as 0.5 for six months if the calculator allows that duration.
Are taxes included?
No. This is a gross interest estimate and does not apply personal tax rules or fees.
Related Calculators
- Interest Calculator — compare simple and compound growth.
- Compound Interest Calculator — account for compounding frequency.
- Future Value Calculator — include periodic payments.
Internal links: compare this result with the Interest Calculator or Compound Interest Calculator.