Compound Interest Calculator
Visualize the power of compound interest and watch your investments grow
Investment Parameters
What-If Scenarios
Double Your Contributions
Start 5 Years Earlier
Compound Growth Formula & Interpretation
Compound formula: A = P × (1 + r/n)^(n × t)，where A is the ending balance, P is the principal, r is the annual return, n is the compounding frequency, and t is years invested. Increasing monthly contributions or investing earlier accelerates exponential growth, and the tool separates principal contributions from interest gains so you can explain performance.
Lump-Sum Investments
Perfect for bonuses or one-time savings—see how long-term compounding builds momentum.
Recurring Contributions
Simulate monthly deposits to evaluate progress toward target balances or retirement needs.
Return Sensitivity
Compare different return assumptions or market volatility to set realistic long-term expectations.
Frequently Asked Questions
How should I choose a return rate?
Reference historical index or bond performance, or test conservative, neutral, and aggressive scenarios.
Are taxes included?
The current model focuses on pre-tax growth; tax inputs for net calculations are planned for future updates.
Can I export charts?
Capture chart images or export CSV output for collaboration or reporting.
Related Guides
Build stronger context around your projections
Pair the calculator with deeper planning guides so the page behaves less like an isolated widget and more like a financial decision hub.
Compound Interest Power
Understand how time, rate assumptions, and contribution cadence change the final result.
Savings Goal Calculator Guide
Turn growth projections into concrete milestone planning and monthly saving targets.
Loan Comparison Calculator Guide
Compare the cost of investing versus paying down debt when cash flow is limited.