Companion to the book “Your Road to a Million”

Compound Interest Calculator

Add several sources, for example an S&P 500 ETF, a savings account, and a European stocks ETF, and see how they grow together over the years.

General settings

Number of years

Currency

Goal (€)

Yearly inflation (%)

Tax rate on gains (%)

Calculation method

Show value in today’s moneySubtracts inflation, so you see what that money will actually buy in the future. Subtract tax on gainsA simplification: as if you sold everything that year and paid the tax rate above on the gain. Tax rules differ by country and by account type, so use the rate that applies to you.

Sources of compound interest

Each source has its own starting amount, monthly deposit, yearly return, and fee. The return minus the fee is the net return the calculator uses. You can add up to six sources.

Result

Growth over time

Hover over or tap the chart to see the values for a given year. The full data is in the tables below.

Breakdown by source

Year-by-year table

How to read this

This is an educational tool, not financial advice or investment advice. It shows a simulation with constant assumptions. In reality, returns change from year to year and are sometimes negative. Past results do not guarantee future results.

The “exact” (monthly) mode assumes deposits at the end of each month and interest added monthly at the same yearly rate. The “as in the book” (yearly) mode counts 12 deposits at once at the end of the year, so the results are a little lower. The 15% tax is applied to the whole gain and is a simplification. Inflation is constant.