Interest Rate Calculator
Calculate the interest rate from principal, final amount, and time period. Works for simple and compound interest.
Enter principal, final amount, and time.
Interest Rate Formulas
Simple: r = (A − P) / (P × t) × 100
Compound: r = [(A/P)^(1/t) − 1] × 100
Compound: r = [(A/P)^(1/t) − 1] × 100
Example: $10,000 grew to $12,000 in 3 years (compound).
r = (12000/10000)^(1/3) − 1 = 0.0627 = 6.27%
r = (12000/10000)^(1/3) − 1 = 0.0627 = 6.27%
Related Calculators
Last updated: 2026-08-08