Compound Interest Calculator
See how your savings or investments grow over time with compound interest.
Compound Interest Calculator
Your Result
How Compound Interest Growth Is Calculated
Compound interest means you earn interest not only on your original amount but also on the interest that has already accumulated. This calculator combines a standard compound interest formula for your initial deposit with a running monthly contribution, so you can see realistic long-term growth for savings accounts, retirement funds, or investment portfolios.
Formula
A = P(1 + r/n)nt, plus the future value of a series of monthly contributions compounded at the same rate.
Where P is the principal, r is the annual interest rate, n is the compounding frequency per year, and t is the number of years.
Frequently Asked Questions
Does compounding frequency really make a difference?
Yes, more frequent compounding (like daily vs annually) results in slightly higher returns because interest starts earning its own interest sooner, though the difference is usually modest at typical rates.
Is this calculator accounting for inflation or taxes?
No, this shows nominal growth only. Real purchasing power and after-tax returns will be lower depending on inflation and your tax situation.
Can I model withdrawals instead of contributions?
Enter a negative number in the monthly contribution field to model regular withdrawals instead.