Why am I up in dollars but down in euros?

Example: +100 $, yet −37.27 €

You buy 10 US shares at 150 $ each, 1,500 $ in total. The euro trades at 1.05 that day: one euro costs 1.05 dollars (EUR/USD). Later you sell them at 160 $ each and receive 1,600 $. In dollars you are up +100 $.

On the day of the sale, though, EUR/USD is 1.15 — the dollar has weakened against the euro. Converted to euros:

• purchase: 1,500 $ ÷ 1.05 = 1,428.57 €
• sale: 1,600 $ ÷ 1.15 = 1,391.30 €
• result: 1,391.30 € − 1,428.57 € = −37.27 €

The stock went up, but in euros you made a loss. The chart shows where the difference comes from.

Why this happens

Your result in euros is not the dollar gain converted at a single rate. It is the difference between two amounts from two different days:

result in euros = sale price at the sale-date rate − purchase price at the purchase-date rate

EUR/USD tells you how many dollars one euro costs, so you get euros by dividing dollars by the rate. When the rate goes up — the euro strengthens and the dollar weakens — the same dollars buy fewer euros. In the example, the 1,600 $ from the sale had to be worth at least 1,428.57 € for you to break even. That only happens if the rate on the sale date is 1.12 or lower. At 1.15 the dollars no longer cover it.

It works the other way too: if the dollar strengthens while you hold the stock, you can be up in euros even if the share price did not move at all.

Stock result vs currency effect

You can split the euro result into two parts that answer different questions:

• Stock result — what the stock itself earned. In the example, the dollar gain at the purchase-date rate: +95.24 €. This part tells you whether the pick was good.
• Currency effect — how much the euro amount changed purely because of the rate: −132.51 €. It has nothing to do with the stock, only with what happened to the dollar while you held it.

Together +95.24 € and −132.51 € make −37.27 €. The split is an illustration, not a separately taxed item: for tax purposes there is one capital gain or loss, calculated from the euro amounts. The split can be done in other ways too — here the stock part uses the purchase-date rate.

How the Finnish Tax Administration calculates it

According to section 2.2 of the Tax Administration’s detailed guidance Arvopaperien luovutusten verotus (taxation of disposals of securities; in Finnish), an acquisition price paid in a currency other than the euro is converted to euros at the exchange rate of the acquisition date. A sale price received in another currency is converted, unless there is other evidence, at the exchange rate of the date the sale price was received. Section 2.3 applies the same conversion to capital losses.

The newer guidance Omaisuuden luovutusvoitot ja -tappiot luonnollisen henkilön tuloverotuksessa (capital gains and losses of individuals, 4 May 2026; in Finnish) puts the sale differently: under section 8.11 a sale price in a foreign currency is converted to euros at the rate of the trade date, and rate changes after the trade date do not affect the capital gain. Section 5.2 names the official ECB rate of the day the contract is signed as the conversion rate. In practice the gap is usually one day: US stock trades now settle one business day after the trade date (T+1, SEC), so the rate may differ slightly. PnlTrack converts the sale at the ECB rate of the trade date — that is our reading of the guidance until the Tax Administration settles the question. ECB rates are in its euro reference rates.

In practice this also means:

• The taxable result is calculated in euros, not in dollars. The trade in the example is a capital loss for tax purposes, even though you were up in dollars. More on deducting it: deducting capital losses.
• Section 2.2 of the securities guidance deducts, besides the acquisition cost, the expenses of producing the gain, such as trading fees. The example and the calculator on this page leave fees out to keep things clear.

How to calculate your own numbers

For each trade you need the dollar amounts and two exchange rates.

1. Convert the acquisition price. Divide the purchase amount in dollars by the EUR/USD rate of the purchase date.
2. Convert the sale price. Divide the sale amount in dollars by the EUR/USD rate of the sale’s trade date (or of the day the sale price was received — see above).
3. Subtract, including fees. Subtract the acquisition cost and the trading fees from the sale price. A positive number is a capital gain, a negative one a capital loss.

Calculator

Enter your own numbers. Enter the rate the way the ECB publishes it: how many dollars one euro costs. The chart shows how the result in euros changes with the sale-date rate — where the line crosses zero, you break even in euros.

To estimate the tax as well, use the capital gains tax calculator.