Finance calculator
Compound Interest Calculator
See how regular contributions and compounding grow your savings over time.
Last reviewed
September 2026
September 2026
Enter your details
Results update privately in your browser.
How we calculate
A transparent estimate you can inspect.
Formula
Compound growth on your initial principal plus the future value of monthly contributions evaluated at the effective periodic rate for your selected compounding frequency.
Privacy
Your values are calculated locally and are not sent to a server by this calculator.
Use with care
Results are for informational purposes, not financial, tax, legal, lending, or investment advice.
Understanding your results
Investment growth is the projected balance less all starting and recurring contributions.
Assumptions and limitations
- Contributions are made at the end of each month.
- Return is an entered assumption, not a guarantee.
Common questions
Before you decide
What assumptions does this use?
The inputs and assumptions are shown on this page; real outcomes can differ.
Does this use my financial data?
No. Inputs stay in your browser.