How Much Do I Need to Invest? Calculator (2026)

By Kestutis Balciunas — European long-term investor, 11+ years self-directed. Reviewed against my editorial process on 4 June 2026.

Last reviewed: 4 June 2026. Some broker links are affiliate links — see my affiliate disclosure. Not investment advice.

Once you have your number, the free ETF Starter Kit shows exactly where to put it — fund, broker and first purchase.

How Much Do I Need to Invest?

This is the question that stops most people before they start — and the honest answer has two halves. To reach a specific goal by a specific date, there is a precise monthly figure, and the calculator below works it out for you. But to begin investing, the answer is: almost nothing. European brokers now let you open a free, automated savings plan and invest from as little as €1 using fractional shares. So use the tool to set a target, but don’t let the number scare you off — starting small today beats waiting until you can start big.

You do not need a lump sum to start

The single biggest myth in investing is that you need thousands of euros to begin. You don’t. A monthly savings plan into a broad, low-cost ETF — set up once and run automatically — is exactly how the large majority of successful long-term investors actually build wealth, and most European brokers let you start one from €1 with no commission. There is no minimum portfolio, no need to time the market, and no requirement to have a windfall first. If the monthly figure the calculator gives you feels out of reach today, start with whatever you genuinely can afford. €25 a month invested consistently is worth infinitely more than €500 a month you keep postponing until conditions feel right.

Why starting now beats starting big

Compounding rewards time far more than it rewards size, which is why the years you spend deliberating cost you more than a smaller starting amount ever could. A modest contribution made in your twenties or thirties has decades to multiply; a much larger one started ten years later never catches up. The calculator makes this visible — shorten the horizon and watch how sharply the required monthly amount rises, because you are asking compounding to do the same job in less time. The lesson is not “invest more”; it is “start sooner and automate it,” then raise the amount as your income grows. Money you invest mechanically every month, regardless of the headlines, is the money that quietly becomes a portfolio.

Working backwards from a goal

If you have a target — a house deposit, a child’s education, a million-euro retirement pot — the tool runs the maths in reverse: it takes the amount you want, your time horizon and a reasonable return assumption, and tells you the monthly contribution that gets you there. Be realistic with the return: a broad global equity portfolio has historically returned somewhere around 6–8% a year before inflation over long periods, but with plenty of volatility along the way, so treat the figure as an estimate, not a promise. Once you know your number, build the actual portfolio in the portfolio builder and keep the costs down with the ETF fee calculator.

Investing for an income goal

If your goal is a monthly income rather than a lump sum — financial independence, early retirement, a passive-income stream — switch the tool to income mode. It converts your desired monthly income into the portfolio size needed to sustain it (using a withdrawal rate you set, with around 4% a common starting point), then solves for the monthly contribution to build that pot. For the full picture on what you’d actually need and how long it lasts, pair it with the FIRE calculator and the safe withdrawal rate calculator. When you’re ready to open an account and start a savings plan, my top pick is Freedom24, with Trade Republic, Interactive Brokers and XTB as alternatives.

Frequently asked questions

How much do I need to start investing in ETFs?

Almost nothing. Most European brokers let you start an automated savings plan into a UCITS ETF from as little as €1 using fractional shares, with no commission. There is no minimum portfolio size. Use the calculator to find the monthly amount that reaches your goal, but you can begin with whatever you can afford today and increase it later.

How much should I invest each month?

It depends on your goal, horizon and what you can afford. The calculator solves for the exact monthly figure to reach a target portfolio or income by a chosen date. As a rule of thumb, invest a consistent percentage of your income (many aim for 10–20%), automate it, and raise it whenever your income rises. Consistency matters far more than the precise amount.

Can I start investing with €100 (or less)?

Yes. Thanks to fractional shares and free savings plans on most European brokers, you can invest €100, €25 or even €1 a month into a diversified ETF. Small amounts compound: the habit and the early start are worth more than the size of the first contribution. Begin small, stay consistent, and scale up over time.

How much do I need to invest to reach €1 million?

It depends on your horizon and return. As an example, starting from a small base and assuming ~7% a year, reaching €1 million takes on the order of €800 a month over 30 years, or considerably more over a shorter period because compounding has less time to work. Enter your own numbers in the calculator to see the figure for your situation.

Is it worth investing small amounts?

Absolutely — arguably more than waiting to invest large ones. A small amount invested early has decades to compound, while a larger amount started years later never fully catches up. Free savings plans make small, regular investing practical and cheap. The most expensive decision is postponing the start; the size of the first contribution barely matters by comparison.

Next: build the portfolio you’ll invest in with the portfolio builder, set your independence target with the FIRE calculator, and pick the funds in the UCITS ETF comparison tool.