Free Interest Calculator - Calculate Earnings & Savings
Calculate simple and compound interest earnings on savings and investments.
Formula & Methodology
Simple interest only grows based on the initial principal, whereas compound interest grows exponentially by earning interest on previously accumulated interest.
- Simple: I = P × r × t
- Compound: A = P(1 + r/n)^(nt)
Worked Example
Using the Interest Calculator: apply the formula above to your input values. For instance, Simple: I = P × r × t, then Compound: A = P(1 + r/n)^(nt). The tool performs each step instantly and shows the result.
Frequently Asked Questions
What is the difference between simple and compound interest?
Simple interest is earned only on the principal, while compound interest also earns on accumulated interest.
How is simple interest calculated?
Multiply the principal by the annual rate and the number of years to get the total interest earned or owed.
Does compounding frequency change my interest?
For compound interest, more frequent compounding produces slightly more total interest over the same period.