About — Compound Interest Calculator
Learn more about Compound Interest Calculator, a free resource for understanding and projecting compound interest, investing, and savings growth.
Compound Interest Calculator is a free online resource built to help people understand how compound interest works and how it can grow savings and investments over time. Our calculators, guides, and comparison tools are designed to be fast, accurate, and easy to use on any device.
Our mission
We believe financial clarity should be free and accessible. By making compound interest visual and interactive, we hope to help more people start investing earlier, save more consistently, and set realistic long-term goals.
How the calculators work
All calculations run directly in your web browser. Enter your starting balance, monthly contribution, expected annual return, time horizon, and compounding frequency, and the calculator instantly projects your total balance, contributions, and interest earned. No account is required, and we do not store your inputs.
Accuracy and methodology
Our compound interest formula follows the standard financial model: A = P(1 + r/n)^(nt) + contributions. We use monthly compounding logic for contributions and display results as projections, not guarantees. Market returns fluctuate, so we encourage users to run multiple scenarios with conservative, moderate, and optimistic assumptions.
Important disclaimer
This website is for educational purposes only and does not provide personalized financial, investment, tax, or legal advice. Always consult a qualified financial professional before making major financial decisions.
Trusted financial partners
We only link to financial services we believe are reputable and relevant to our readers. Popular options for low-cost investing and savings include Vanguard , Fidelity , Charles Schwab , Betterment , Wealthfront , Marcus by Goldman Sachs , and Ally Bank .
Affiliate disclosure
Some links on this site are affiliate links. We may earn a commission if you click through and open an account or make a purchase, at no additional cost to you. Affiliate income helps support the ongoing development of the site.
Get in touch
Have feedback or a suggestion? Visit our contact page to send us a message. We read every message and use feedback to improve the calculators and guides.