Interest Rate Calculator
Reverse-calculate the hidden interest rate from known principal, final amount, and time period.
Required Interest Rate
8.45% compound
Simple Rate
10.00%
Compound Rate
8.45%
Total Growth
$5,000
How to Find the Interest Rate
This calculator reverse-engineers the rate using both simple and compound interest formulas.
Simple Rate: r = (A β P) / (P Γ t)
Compound Rate: r = (A/P)1/t β 1
Worked Example
Investment grew from $8,000 to $12,500 in 4 years:
- Simple rate: 14.06%/year
- Compound rate: 11.82%/year