Capital Gains Tax Basics for Investors

The Trigger Is Realization

Start with the calming part, because it is the thing most anxious searchers do not know.

Capital gains tax is generally realization based: the charge arises when you dispose of an asset, not while you hold it. A holding that has tripled and sits untouched has produced no taxable gain. The paper profit is not income until you turn it into something.

This is why the distinction between realized and unrealized gains is a tax concept before it is a performance one.

Two caveats worth stating plainly. Some countries tax investment wealth by other means, such as an annual charge on holdings, so "no sale, no tax" is a description of how capital gains tax works rather than a promise about your total tax bill. And a disposal is broader than a sale: switching funds, or being bought out in a takeover, is usually a disposal even though it does not feel like selling.

What the Gain Is Calculated On

The gain is what you got minus what it cost you, with allowable costs included on both sides.

A Worked Example

You buy 100 shares at EUR 40 and pay EUR 10 in commission. Later you sell them all at EUR 62, paying EUR 10 again.

Cost:      (100 x 40) + 10 = EUR 4,010
Proceeds:  (100 x 62) - 10 = EUR 6,190
Gain:      6,190 - 4,010   = EUR 2,180

Note the fees pull in opposite directions: the buying fee raises your cost, the selling fee reduces your proceeds. Both shrink the gain, and both are easy to forget, which means people routinely overstate what they owe.

The Three Things That Change the Number

Which Lot You Sold

If you bought the same share on several occasions at different prices, "I sold 100 shares" is ambiguous until you say which 100.

Buy 100 at EUR 40 and later 100 more at EUR 55, then sell 100. Your cost is EUR 4,000 or EUR 5,500 depending on which batch went, and the gain differs by EUR 1,500 accordingly. Countries prescribe a method: first in first out, weighted average cost, or occasionally letting you nominate the lot.

This is why cost basis has to be tracked per lot rather than as a single blended number. Once the detail is lost, you cannot reconstruct which purchase you sold.

Holding Period

Some systems charge less the longer you have held. Others make no distinction at all. Both approaches are common in Europe, and the two examples below happen to be one of each, which is a useful accident.

Currency

Here is the one that catches European investors, and almost nothing written for a general audience explains it.

If you buy an asset priced in a foreign currency, your gain is measured in your currency. The asset can be completely flat in its own currency and still produce a taxable gain.

You buy 100 shares of a US stock at USD 100 when the rate is 1.20 dollars to the euro. Later you sell at USD 100, unchanged, when the rate is 1.05.

Cost:     100 x (100 / 1.20) = EUR 8,333
Proceeds: 100 x (100 / 1.05) = EUR 9,524
Gain:     EUR 1,190 (+14.3%)

The share did nothing. The dollar strengthened, and in euro terms you made EUR 1,190, which is a real gain and is potentially taxable. Our article on currency gain covers how to see this separately from the asset's own performance.

The practical consequence is that the exchange rate on the trade date of each transaction is part of your tax record, not an optional refinement.

Rates Vary Enormously Across Europe

There is no European capital gains tax. There are national ones, and they differ by more than most people expect, which is why a single trade produces wildly different bills depending on where you are tax resident.

Take the EUR 2,180 gain from the worked example above.

Germany

Investment income is taxed at a flat 25% withholding tax (Abgeltungsteuer) plus a 5.5% solidarity surcharge, giving a combined 26.375%, with church tax on top for members. There is an annual allowance (Sparer-Pauschbetrag) of EUR 1,000 per taxpayer, doubled for married couples filing jointly. There is no distinction between short and long holding periods (PwC Worldwide Tax Summaries, Germany, reviewed 30 March 2026).

Gain:            EUR 2,180
Less allowance:  EUR 1,000
Taxable:         EUR 1,180
Tax at 26.375%:  EUR 311

Romania

The general rate on net capital gains is 16%. But where the transfer goes through a Romanian intermediary, tax is withheld at 3% for securities held longer than 365 days and 6% for those held 365 days or less. Broker fees are deductible, and individuals report through an annual return by 25 May following the year of the transaction. Health insurance contributions may also apply above an income threshold (PwC Worldwide Tax Summaries, Romania, reviewed 30 March 2026).

Held over 365 days,  3%:  EUR 65
Held 365 days or less, 6%: EUR 131

The Records You Need

This is the practical payoff, and it is the same list regardless of which country's rules you are under.

How Turbobulls Keeps These Records

Cost basis is tracked per lot, so each purchase keeps its own price and date rather than dissolving into an average. Multi-currency holdings are handled natively across 30+ currencies with the exchange rate applied on the trade date, which is exactly the figure the currency example above turns on. Dividend transactions record the withholding tax deducted at source.

Turbobulls also separates a gain into its capital and currency components, so the EUR 1,190 in the example above is visible as currency rather than hidden inside a single number. That split sits on the paid plan, as does the realized-versus-unrealized breakdown per holding.

For handing anything to an accountant: export is available on every plan, free included, and is never paywalled.

The Full Picture: Read These Next

Frequently Asked Questions

Q: Do I pay tax if I do not sell?

Q: What about dividends?

Q: Does switching funds count as a sale?

Q: What if I sold at a loss?

Turbobulls is a tracking and analytics tool, not an investment adviser. Nothing here is investment, tax, or legal advice. Investing involves risk, including loss of principal. Do your own research or consult a licensed professional.