Before You Start
- Basic understanding of ETFs and stocks (for example, what is an ETF, how do you buy one)
- Access to at least one European-friendly broker (e.g., Trade Republic, DEGIRO, Scalable Capital)
- Willingness to register for a free account on a backtesting tool (e.g., Portfolio Visualizer, Backtest, Curvo, or JustETF)
- List of EUR-denominated ETFs or stocks you wish to analyse
- Awareness of your investment time horizon and risk tolerance
Time needed: 45–90 minutes (including setup and your first test)
What you'll need: Broker account, internet access, and a backtesting tool (free or paid)
Portfolio backtesting is an essential skill for European investors who want to make evidence-based decisions with ETFs and stocks. In 2026, intuitive tools make it possible to simulate your investment ideas using real historical data—before you commit real money. This tutorial will walk you through the process, step by step, using EUR-denominated assets and platforms available to Europeans.
As covered in our Ultimate 2026 ETF Investing Playbook for European Retail Investors, consistently reviewing and optimizing your portfolio is key to long-term performance. Backtesting is one of the best ways to do this. Below, you’ll learn how to use leading backtesting tools, avoid common pitfalls, and integrate backtesting into your regular investment process.
Step 1: Choose a Portfolio Backtesting Tool Accessible in Europe
What to do: Select a backtesting tool that supports European tickers, EUR as base currency, and UCITS ETFs. Recommended options for 2026 include:
- Portfolio Visualizer (free tier, advanced paid features)
- JustETF (excellent for UCITS ETFs, limited free backtesting, paid premium analytics)
- Curvo (simple, EUR-focused, paid plans only)
- Backtest.com (modern interface, growing European coverage)
Why it matters: Many global backtesting tools focus on US-domiciled funds, which are often unavailable to Europeans due to PRIIPs regulation. Choosing a Europe-ready platform ensures you can test with the actual ETFs and stocks available to you.
What can go wrong: Using a tool that lacks European assets can give misleading results. For example, backtesting SPY (US S&P 500 ETF) is not actionable for most EU retail investors—use UCITS equivalents like CSPX or VUSA instead.
Pro Tip
If you’re new to backtesting, start with JustETF’s free Portfolio Analyzer to visualize performance of common EUR-denominated ETFs. For deeper analytics (such as risk metrics or custom rebalancing), try Portfolio Visualizer’s free tier.
Step 2: Gather Your EUR-Denominated ETFs and Stocks
What to do: Make a list of ISINs or ticker symbols for the funds and stocks you want to test. For example:
- iShares Core MSCI World UCITS ETF (EUR) – IWDA (ISIN: IE00B4L5Y983)
- Vanguard FTSE All-World UCITS ETF (EUR) – VWCE (ISIN: IE00BK5BQT80)
- iShares Core S&P 500 UCITS ETF (EUR) – CSPX (ISIN: IE00B5BMR087)
- ASML Holding NV (Euronext Amsterdam) – ASML
You can find these in your broker’s search tool (e.g., in Trade Republic, tap “Search” and enter the ETF/stock name or ISIN).
Why it matters: EUR-denominated and UCITS-compliant ETFs are tax-efficient and available to all European investors. Using the correct ISIN ensures you’re testing the right product.
What can go wrong: Mixing up tickers (e.g., US-domiciled vs. UCITS versions) will distort your results, especially regarding tracking difference and taxation.
Pro Tip
Unsure which ETF to use? See our comparison: VWCE vs. IWDA in 2026: Which Global Equity ETF Should Europeans Choose?
Step 3: Set Up Your Portfolio in the Backtesting Tool
What to do: Register (if needed) and log into your chosen tool. Create a new portfolio and enter your selected assets and their weights. For example:
- 60% IWDA (iShares Core MSCI World UCITS ETF)
- 20% CSPX (iShares Core S&P 500 UCITS ETF)
- 10% VWCE (Vanguard FTSE All-World UCITS ETF)
- 10% ASML (Euronext Amsterdam stock)
In Portfolio Visualizer: Go to “Backtest Portfolio”, select EUR as currency, and enter your tickers/ISINs and weights.
In JustETF: Click “My Portfolio” → “Create Portfolio” → Add each ETF/stock by ISIN/ticker and set allocation percentages.
Why it matters: Correct asset allocation is the foundation of any analysis. Entering weights accurately ensures the test reflects your real intentions.
What can go wrong: Forgetting to set the currency to EUR or entering incorrect weights will give you misleading data. Double-check before proceeding.
Pro Tip
When testing, keep your portfolio simple at first—2–4 assets. Complexity can make it harder to interpret results and spot actionable trends.
Step 4: Configure Backtest Parameters (Timeframe, Rebalancing, Contributions)
What to do: Set your desired backtest timeframe (e.g., 2016–2026), rebalancing frequency (e.g., annually), and any regular contributions (e.g., €200/month).
In Portfolio Visualizer: Under “Settings”, select “Start Year” (e.g., 2016), “End Year” (2026), and “Rebalancing” (e.g., annual/semi-annual). Enter “Periodic Contributions” if you want to simulate monthly investing.
In JustETF: Use the “Savings Plan” feature to add monthly contributions. Set rebalancing under “Portfolio Settings”.
Why it matters: Simulating periodic investing (like monthly savings) and rebalancing reflects real-world investing habits and gives more realistic results.
What can go wrong: Using an unrealistically long or short timeframe can skew results. If an ETF launched recently, you’ll see data only from its inception date. Always check for data gaps.
Pro Tip
If you want to compare buy-and-hold vs. regular investing, run two separate backtests—one with a lump sum, one with monthly contributions.
Step 5: Analyse Results—Performance, Risk, and Drawdowns
What to do: Review the summary statistics and charts provided by the tool. Focus on:
- Annualised return (in EUR)
- Volatility (standard deviation)
- Maximum drawdown (biggest peak-to-trough loss)
- Sharpe ratio (risk-adjusted return)
- Portfolio balance over time
You should now see charts showing how your portfolio would have performed over the selected period, with values in EUR (e.g., “Portfolio value at end: €15,600”).
Why it matters: These metrics help you judge if your risk/reward profile matches your goals. For example, a Sharpe ratio above 1 is generally considered good for diversified portfolios.
What can go wrong: Ignoring drawdowns or volatility can leave you exposed to more risk than you’re comfortable with, especially during market crashes.
Pro Tip
Compare your results to a simple benchmark, such as a 100% IWDA or CSPX portfolio. This helps you see if your added complexity is actually improving results. For more on CSPX, see The Ultimate 2026 Guide to Investing in CSPX.
Step 6: Consider Costs, Taxes, and Limitations
What to do: Adjust for realistic costs and taxes. Most tools let you input an estimated Total Expense Ratio (TER) for each ETF and a transaction cost per trade (e.g., €1). Taxes are trickier: very few tools model European capital gains or dividend taxes accurately.
In Portfolio Visualizer: Enter “Expense Ratio” per asset. Add “Transaction Fee” if you want to simulate broker costs.
In JustETF: Expense ratios for each ETF are included automatically. You can edit portfolio settings to add transaction costs.
Why it matters: Ignoring fees and taxes will overstate your real returns. For a deeper look at hidden ETF costs, see How to Spot Hidden ETF Costs: A Guide for European Investors.
What can go wrong: Underestimating costs can make risky or expensive strategies look attractive on paper. Tax regimes also change—see Germany’s 2026 Tax Law Overhaul for current details.
Pro Tip
Always check your broker’s actual costs—many European brokers offer commission-free ETF savings plans, but may charge for other trades or currency conversion.
Step 7: Integrate Backtesting Into Your Regular Investment Reviews
What to do: Schedule a portfolio review every 6–12 months. Re-run your backtests with updated asset choices, new ETFs, or changed weights. Note any changes in performance or risk profile.
For example, after a year, you might swap a sector ETF for a broader fund or adjust allocations in light of personal risk changes.
Why it matters: Markets, products, and your own circumstances evolve. Regular backtesting helps you stay on track and avoid “set-and-forget” complacency.
What can go wrong: Overfitting—constantly tweaking your portfolio based on past data—can lead to poor future performance. Use backtesting as a guide, not a guarantee.
Pro Tip
Document each backtest (date, settings, results) in a spreadsheet or notebook. This builds your own personal track record and decision log.
Common Mistakes in Portfolio Backtesting (And How to Avoid Them)
- Using US-domiciled ETFs instead of UCITS versions—results won’t be actionable for Europeans.
- Ignoring fees and taxes—always input realistic expense ratios and transaction costs.
- Backtesting too short a period—aim for at least one full market cycle (7–10 years if possible).
- Overfitting—don’t chase the “best” historical allocation; focus on robust, simple strategies.
- Not checking for survivorship bias—beware if the tool only lets you select current ETFs (failed funds are often missing from history).
Next Steps
- Try backtesting your own portfolio idea with EUR ETFs and stocks using JustETF or Portfolio Visualizer today.
- For asset allocation inspiration, see ETF Asset Allocation Strategies: Building a Core Portfolio for Europeans in 2026.
- Curious about thematic or income-focused portfolios? See How to Invest in Thematic ETFs in Europe and Dividend ETF Laddering: Building Steady EUR Income Every Month.
- Make backtesting a core part of your annual investment review for better, data-driven decisions.
Disclaimer: This article is for educational purposes only and does not constitute financial advice. Always do your own research and consider consulting a qualified financial advisor before making investment decisions.