Free compound interest tool
Interest Calculator
Estimate future value, total interest, and long-term growth using principal, annual rate, years, and monthly contributions.
Calculator
Estimate future growth
Enter your starting amount, annual rate, years, and monthly contribution to estimate ending balance and total interest earned.
Estimated future value
$44,000
ending balance
Total interest$10,000
Total contributed$34,000
Growth multiple1.29x
Estimated using monthly compounding.
Why it matters
See the power of compounding
Even moderate annual returns can grow significantly over time, especially when recurring monthly contributions are added.
Estimate savings growth
Compare contribution habits
Visualize total interest earned
Simple mobile-friendly tool
How it works
About this calculator
This calculator uses monthly compounding to estimate how your balance may grow over time based on an initial amount, annual interest rate, and recurring monthly contributions.
FAQ
Frequently asked questions
What is compound interest?
Compound interest means interest is calculated on both the original amount and previously earned interest.
Why do monthly contributions matter?
Recurring contributions increase the base that compounds over time, which can significantly raise ending balance.
Does this include taxes or fees?
No. This calculator gives a simplified estimate and does not account for taxes, fees, or investment risk.
© 2026 Interest Calculator • Free online growth estimator • Calculator Center
Privacy: This site provides informational estimates only and does not directly collect personal financial data through this page.
Terms: Results are estimates and should not be considered financial, legal, tax, or investment advice.
Terms: Results are estimates and should not be considered financial, legal, tax, or investment advice.