Compound Interest
Project how a starting balance grows with optional monthly contributions, tax drag, and scenario comparison. Enter principal, rate, horizon, and compounding frequency to see future value and effective annual rate.
Estimates only — not financial advice.
1Input Details
Scenario A
€
%
€
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Capital gains tax reduces effective return
Scenario A growth
How it works
How to use
- Enter starting amount, expected annual return, time horizon, and optional monthly savings.
- Turn on scenario comparison to place two setups side by side in the results.
- Read future value, total contributions, growth, and effective annual rate (EAR) in the results column.
How it works
The tool projects wealth in monthly steps: each month the balance grows by one-twelfth of your after-tax annual rate (if you set a tax rate, it scales down the return for a simple drag estimate), then adds your monthly contribution. The compounding dropdown mainly affects the effective annual rate (EAR) shown—so you can compare how often interest is credited for the same stated annual return. It does not switch the balance simulation to quarterly or yearly steps.