The detailed guide below is currently available in English.
Where the fees hide
Exchanges usually quote a maker/taker fee as a percentage of each trade’s value, and both legs of a round trip cost you: one fee when buying, another when selling. On a leveraged or high-frequency strategy those percentages compound into a serious drag, and spreads, withdrawal fees, and conversion charges can add more. Model your actual fee tier rather than the headline 0% marketing number.
A volatile market needs a wider lens
Crypto can deliver double-digit moves in a day, so a single buy-sell snapshot says little about a strategy. Consider what a 30% drawdown after your buy would do to the plan, whether you would hold or exit, and how taxes apply — in the US, each sale or swap is a taxable event just like a stock. Position sizing you can live with beats any projected return.
Repères pour la France
Les principaux repères locaux à connaître pour les calculs financiers en France – ils diffèrent nettement des normes américaines :
- TVA: Taux normal 20 %, intermédiaire 10 %, réduit 5,5 %, particulier 2,1 %. Les prix affichés sont toujours TTC (toutes taxes comprises).
- Impôt sur le revenu (barème 2025): Barème progressif par part : 0 % jusqu'à 11 497 €, puis 11 %, 30 %, 41 % et 45 % au-delà de 180 294 €, avec décote sous 19 174 € (célibataire).
- Cotisations sociales: Part salariale ≈ 22 % du brut (sécurité sociale, retraite, chômage) ; un salaire net correspond à environ 78 % du brut.
- SMIC 2025: 1 801,80 € brut par mois (≈ 1 426 € net) sur la base de 35 heures hebdomadaires.
- Pourboire: Le service est compris dans les prix en café-restaurant depuis 1982 ; arrondir l'addition reste un geste apprécié, sans obligation.
Mis à jour : octobre 2026 · valeurs 2025, sources officielles ci-dessus.
Questions fréquentes
How are the fees calculated?
Each fee applies to that leg’s dollar value: the buy fee to the amount you paid, the sell fee to the amount you received. Enter 0 if your exchange charges no trading fees.
Can I enter fractions of a coin?
Yes — crypto trades in fractions, so 0.5, 0.021, or any decimal quantity works. The math scales the fees proportionally.
Do I owe tax on crypto gains?
In the US and most countries, yes: selling or spending crypto at a gain is a taxable event. Short-term gains usually follow income tax rates and long-term gains the capital gains schedule.