ETF Savings Plan Calculator: What Does €100 a Month Actually Get You?

€100 a month doesn't sound like much. But invested consistently in an ETF savings plan over the years, that amount builds serious wealth. The question is: how much exactly? This article shows the numbers at different time horizons and return rates — concrete figures, no financial jargon.

What Is an ETF Savings Plan?

An ETF savings plan is an automated recurring investment set up with a broker. Every month, a fixed amount goes into one or more ETFs. ETFs (Exchange Traded Funds) track an index such as the MSCI World or the S&P 500, spreading your risk across hundreds or thousands of companies.

The advantage over individual stocks: you need no market timing, no stock analysis. You buy automatically — at high prices and low prices alike. This principle is called the cost averaging effect: when prices are low, you get more shares; when prices are high, you get fewer. Over time, your average entry price smooths out.

ETF Savings Plan Calculator: The Formula

Calculating a savings plan uses the formula for the future value of an ordinary annuity:

Final capital = monthly rate × ((1 + r)^n - 1) / r

• Monthly rate = monthly contribution (e.g. €100)
• r = monthly interest rate (annual return / 12)
• n = number of months

At a 7% annual return and €100 a month over 30 years, the result is:

r = 0.07 / 12 = 0.005833
n = 30 × 12 = 360
Final capital = 100 × ((1.005833)^360 - 1) / 0.005833
Final capital ≈ €121,997

You contributed €36,000 of your own money. The rest — roughly €86,000 — comes from the compound interest effect.

Investing €100 a Month: What Are the Results?

The table below shows what a €100 monthly contribution grows to at different return rates and time horizons:

Return p.a.	After 10 years	After 20 years	After 30 years
5%	€15,528	€41,103	€83,226
7%	€17,308	€52,093	€121,997
9%	€19,351	€66,789	€183,074
11%	€21,700	€86,564	€280,452

Your own contributions: €12,000 (10 yrs), €24,000 (20 yrs), €36,000 (30 yrs). Everything above that is returns.

At 7% return over 30 years, you put in €36,000 and get back almost €122,000. That is more than three times your total contributions. And the majority of the growth happens in the final 10 years.

What Return Is Realistic?

Historical returns depend on the index you choose. Here is an overview of average annual returns (before taxes, before inflation):

Index	Period	Return p.a.
MSCI World	1975–2024	approx. 9.1%
S&P 500	1975–2024	approx. 10.5%
MSCI Emerging Markets	2000–2024	approx. 7.0%
DAX	1988–2024	approx. 8.3%

A conservative assumption is 7% gross. After inflation (approx. 2%), the real return is around 5%. These are long-run averages — in any individual year, returns can swing significantly.

ETF Savings Plan: €200 and €500 a Month

Not everyone can or wants to save €100. The calculation scales linearly: double the monthly rate, double the final amount. Here is the comparison at 7% return:

Monthly rate	After 10 years	After 20 years	After 30 years
€50	€8,654	€26,047	€60,999
€100	€17,308	€52,093	€121,997
€200	€34,616	€104,186	€243,994
€500	€86,541	€260,465	€609,985

With €500 a month and 30 years of patience, €180,000 in contributions turns into over €600,000. For many people, that is enough for a solid retirement.

How Taxes and Costs Change the Picture

Taxes

In Germany, capital gains are subject to the Abgeltungsteuer (flat withholding tax) of 26.375% (including solidarity surcharge). However, there is a saver's allowance (Sparerpauschbetrag) of €1,000 per person (€2,000 for married couples), meaning gains up to that threshold are tax-free each year. Equity ETFs also benefit from the Teilfreistellung (partial exemption): 30% of returns are exempt from tax.

In practice, you pay an effective tax rate of around 18.5% on equity ETF gains — and only when you sell. While you hold, your capital grows tax-deferred. That is a significant advantage over savings accounts and bonds, where interest is taxed annually.

Costs

ETFs carry ongoing costs known as the TER (Total Expense Ratio). For an MSCI World ETF, this is typically 0.10–0.20% per year — a fraction of what actively managed funds charge (often 1.5–2%). The TER is deducted directly from the fund assets and is already reflected in the price performance you see.

Accumulating vs. Distributing ETFs

ETFs come in two variants:

• Accumulating: Dividends are automatically reinvested. The compound interest effect runs on its own.
• Distributing: Dividends are paid out to your account. You need to reinvest them manually to capture the full compounding benefit.

For long-term wealth building through a savings plan, accumulating ETFs are simpler and often more tax-efficient. Distributing ETFs make more sense if you want to use your annual tax-free allowance each year, or if you need regular income.

The Most Common Mistakes With ETF Savings Plans

1. Pausing the plan during a crash

Market crashes feel bad. But that is exactly when you are buying cheaply. Anyone who paused their savings plan during the 2020 Covid crash missed the fastest stock market recovery in history. Staying the course is the single most important success factor.

2. Buying too many ETFs

A single MSCI World ETF holds over 1,500 companies from 23 developed countries. Add an Emerging Markets ETF and you cover 90% of the global economy. Three or four ETFs are more than enough for most investors.

3. Waiting for the perfect entry point

Market timing does not work — decades of research confirm this. Investors who contribute regularly almost always outperform those who wait for the perfect moment. Time in the market beats timing the market.

4. Ignoring inflation

€122,000 in 30 years is worth less than €122,000 today. At 2% inflation, that sum has the purchasing power of roughly €67,000 in today's money. Always plan with real values. Our inflation calculator helps you do exactly that.

ETF Savings Plan vs. Savings Account

Many people park their money in a savings or money market account. Does that make sense? A comparison with €100 a month over 20 years:

Investment	Return p.a.	Final capital	Gain
Savings account	2.5%	€31,097	€7,097
ETF (MSCI World)	7.0%	€52,093	€28,093

The ETF savings plan generates more than four times the gain. Of course, an ETF fluctuates more — but over a 20-year period, a broadly diversified global ETF has never produced a loss in historical data.

The recommendation: keep your emergency fund in a savings account, build long-term wealth in an ETF savings plan. How large your emergency fund should be is answered by our emergency fund calculator.

Step by Step: How to Start Your ETF Savings Plan

1. Set your monthly rate. How much can you spare each month? Start small and increase later.
2. Choose an ETF. For beginners: an accumulating MSCI World ETF with a low TER.
3. Open a broker account. Neo-brokers offer free savings plans. Compare execution fees and ETF selection.
4. Set up your savings plan. Choose amount, ETF, and execution date — done.
5. Let it run. Don't check your portfolio every day. Rebalancing once a year is enough.

Conclusion: Starting Early Beats Everything

An ETF savings plan is no secret — but it is one of the most powerful tools for building wealth. The numbers speak for themselves:

• €100 a month grows to roughly €122,000 at 7% return over 30 years.
• Only €36,000 of that is your own money — the rest is compound interest.
• The earlier you start, the harder time works for you.

The best time to start a savings plan was ten years ago. The second best time is today.

More useful calculators: Compound interest calculator · ROI calculator · FIRE calculator · Rule of 72 calculator