Compound Interest Calculator
Estimate the future value and total interest of savings or an investment from a principal, annual rate, term and compounding frequency — 100% in your browser, no upload.
Final amount: 1628.89Total interest: 628.89
🔒 Calculated in your browser — nothing is uploaded. This is a mathematical estimate, not financial advice.
How the estimate works
Enter a principal, an annual interest rate, a number of years and how many times interest compounds each year. The tool applies the standard formula A = P × (1 + r/n)^(n×t), where P is the principal, r is the annual rate as a decimal, n is the compounds per year and t is the number of years. It instantly shows the estimated final amount and the total interest earned. Figures are shown to two decimals for readability while the underlying math stays exact. Uses plain numbers with no currency, so read the result in whatever units you entered.
Estimate only, not financial advice
This is a mathematical estimate that assumes a fixed rate and regular compounding. Real accounts and investments involve variable rates, fees, taxes, deposits and withdrawals, so actual returns will differ. Use it to compare scenarios and build intuition, not as a guarantee or a substitute for advice from a qualified financial professional.
Frequently asked questions
What formula does this calculator use?
The standard compound interest formula A = P × (1 + r/n)^(n×t), where P is the principal, r is the annual rate as a decimal, n is the number of compounds per year, and t is the number of years. Total interest is simply A − P.
Why does more frequent compounding give a larger amount?
Each time interest compounds it is added to the balance and starts earning interest itself. Compounding monthly (n=12) applies this more often than annually (n=1) at the same nominal rate, so the final amount is slightly higher.
Is anything uploaded to a server?
No. Every calculation runs entirely in your browser with JavaScript. Nothing you type is sent anywhere or stored.