About CompoundCalc
CompoundCalc is a free, no-signup tool built to help anyone visualize how compound interest and regular contributions transform modest savings into long-term wealth. We built it because most online calculators are either too simplistic to be useful or so cluttered with ads they obscure the math underneath.
What this tool does
- Models lump-sum investments and recurring monthly contributions (SIP)
- Supports annual, monthly, and daily compounding
- Visualizes the contribution-vs-interest split with an interactive chart
- Lets you share configurations via URL and export the chart as PNG
What this tool does not do
It does not adjust for taxes, inflation, fees, or variable returns. Real markets fluctuate; this calculator assumes a constant annual rate so you can reason about the underlying mechanics. Nothing here constitutes financial advice — please consult a qualified advisor before making investment decisions.
How the math works
The calculator simulates growth month-by-month. Each month the monthly contribution is added to the running balance, then the balance is compounded at the rate corresponding to your chosen frequency. The closed-form formula A = P(1 + r/n)nt covers the lump-sum case; the simulation generalizes it to handle ongoing contributions correctly.
Privacy
All calculations happen in your browser. No data is sent to a server. Theme preference is stored locally so the app remembers your choice between visits.