To track net worth in multiple currencies, you convert every foreign balance into one base currency, usually the euro, at one consistent rate such as the European Central Bank (ECB) reference rate. Because that rate changes every working day, your net worth moves even when you trade nothing: in 2025, a $50,000 holding lost €5,786 in euro terms through the exchange rate alone.
Many Europeans hold foreign currency without noticing, since US shares and many ETFs are quoted in dollars, and Revolut lets you hold 38 currencies in one app. This article covers which rate to use, how to separate the currency effect from the asset's own return, and how trackers handle it.
Which exchange rate should you use for your net worth?
For tracking, the most practical choice is the ECB euro reference rate, published for 29 currencies at around 16:00 CETon every working day except TARGET closing days. Because it is one public figure per day, you can apply it to every account and look it up later, which keeps your history consistent. The ECB says the rates are for information purposes only, and that suits a net worth overview, where you measure value rather than exchange money.
The rate you get when you actually convert is different, since a bank or broker adds a margin or fee to the mid-market rate (the midpoint between buying and selling prices). DEGIRO, for example, charges 0.25% for conversion through its Auto FX trader, built into the price, according to its tariff overview from 1 January 2026. That cost belongs in your transaction costs, not in the daily valuation of what you hold.
How do currency moves change your net worth without a trade?
A currency move changes the euro value of a foreign holding even when its price in its own currency stays the same. On 2 January 2025 the ECB rate was 1.0321 dollars per euro, and on 2 January 2026 it was 1.1721, so the euro rose by about 13.6% against the dollar. The table shows what that did to $50,000 in a US-listed ETF, once with an unchanged dollar price and once with a hypothetical 10% gain in dollars.
| 2 January 2025 | 2 January 2026, price unchanged | 2 January 2026, price +10% | |
|---|---|---|---|
| Value in dollars | $50,000 | $50,000 | $55,000 |
| ECB rate (USD per EUR) | 1.0321 | 1.1721 | 1.1721 |
| Value in euros | €48,445 | €42,658 | €46,924 |
| Change in euros | −€5,786 (−11.9%) | −€1,521 (−3.1%) |
The second scenario shows why the currency effect and the asset return need to be read separately. In dollars the ETF gained 10%, yet in euros it lost 3.1%, because the currency effect of −11.9% was larger than the gain on the fund. Judged on the euro total alone it looks like a poor investment, while the exchange rate was the real cause. Our guide to calculating investment returns explains how deposits and timing affect the return figure as well.
Debts in a foreign currency follow the same logic and grow in euros when that currency strengthens. For box 3, the Dutch tax on savings and investments, the Belastingdienst asks you to convert foreign-currency assets and debts at the 1 January rate. How box 3 then taxes savings is explained in box 3 tax on savings in 2026.
How do net worth trackers handle multiple currencies?
Most trackers for international users let you pick a base currency and convert everything into it. Kubera converts an amount entered with its own currency code at the latest exchange rate, keeps the original value and lets you switch portfolio currency at any time. Finary sets one currency for the whole account, chosen from EUR, USD, CHF, GBP, SGD and CAD, with BTC and ETH reserved for Finary Plus members. In getquin you set a default currency on the portfolio dashboard, after which all totals are converted automatically. None of these help pages names its source for exchange rates. Our comparison of the best net worth tracker for Europe covers the other differences.
How Gylder fits in
Gylder (gylder.nl) is a net worth tracker, not a budgeting app, and it values everything you hold in euros at official ECB rates, including for past dates. Viewing your wealth in another currency is not available yet, although the features page says it is on the way.
What this doesn't tell you
The example uses two real ECB rates but a hypothetical fund return, and other dates would give another outcome. It also leaves out currency-hedged ETF share classes and tax rules outside the Netherlands. This article is general information, not financial advice.
Frequently asked questions
Is an ETF quoted in euros free of currency risk? Not necessarily, because the quote currency only tells you how the fund is traded. A world ETF listed in euros still owns mostly non-euro shares, so its euro price moves with those currencies too. In the MSCI World, which many of these ETFs track, US companies make up more than 70% of the index, according to MSCI.
Which exchange rate does the Belastingdienst use for box 3? The Belastingdienst asks you to convert foreign-currency assets, debts and cash into euros at the exchange rate of 1 January, and refers to the ECB website for that rate.
Should I use my bank's exchange rate to value my net worth? A single reference rate such as the ECB rate is more consistent for a daily overview, because bank rates include a margin and differ per provider. Your bank's rate only matters when you actually convert money.