Compound Interest Calculator
Calculate how your money grows over time — through the power of compound interest.
Tip
The earlier you start, the stronger compound interest works. Just 10 years difference can double the result.
Want to include your savings plan in your monthly budget?
Start for free →Frequently asked questions about compound interest
What is compound interest?
Compound interest means you earn interest not only on your deposited money, but also on previously earned interest. Your money grows exponentially rather than linearly.
What return is realistic?
A broadly diversified ETF (e.g. MSCI World) has historically achieved about 7% p.a. before inflation. Conservative estimates use 5–6% p.a.
How often is interest calculated?
This calculator compounds monthly — your savings rate is invested each month and returns are credited monthly.
What is the Rule of 72?
Divide 72 by your interest rate and you'll know how many years it takes to double your money. At 7% = about 10 years.
What's better — a large lump sum or small monthly amounts?
Both work, but starting early matters more than the amount. €200/month from age 25 often beats €400/month from age 35 — thanks to compound interest.
What's the difference between interest and compound interest?
Simple interest: you only earn on your deposited capital. Compound interest: you also earn on previously earned interest. The difference becomes enormous over the years.
Are taxes included?
No. Depending on which country you live in, taxes on capital gains may apply. The actual result may therefore be lower.
How do I start an ETF savings plan?
The easiest way is an app like Revolut — ETF savings plan from €1/month, set up in minutes.