Capital gains simulator (form 2086)

The numbers are those of the lines of form 2086; the gain on a sale is l.218 − l.223 × l.217 / l.212. A sale that is not reliable stays listed, outside the totals.

Four points the official guidance does not settle. Each is computed with the reading used and with the other one: here is what it changes to your 2025 tax.

• Rewards (staking, interest, airdrops) i×No guidance sets the acquisition price of a staking reward or an airdrop for form 2086. The official commentary deems an asset whose cost cannot be justified to have been acquired for nothing (BOI-RPPM-PVBMC-30-20, § 90); a reward taxed as income when received could enter at its value that day. A zero price makes you pay more: it is the default reading.
  Reading used: zero acquisition price. Other reading: value on the day received. This choice changes nothing for you in 2025 (tax difference, computed from known data: -5 €). On your data, the reading that makes you pay the most: zero acquisition price.
• Nexo EURX i×EURX represents euros held at Nexo. No text addresses it; Crypto Master files it among tokens. As a “digital asset”, buying it with euros is an acquisition and selling it a sale; as “currency”, these are exchanges, and a crypto sold for EURX is a sale.
  Reading used: digital asset. Other reading: currency (euro). This choice changes nothing for you in 2025 (tax difference, computed from known data: 0 €).
• Stablecoins i×The law defers tax on exchanges without balancing payment between digital assets (French tax code, art. 150 VH bis, II-A). Neither the official commentary nor the form’s notice treats stablecoins separately: swapping them for another crypto is therefore read as a deferred exchange. The other reading — electronic money tokens under MiCA, treated as currency — turns each of these exchanges into a sale.
  Reading used: digital assets, deferred exchanges. Other reading: currency, taxable exchanges. Point to have checked by a professional: 2025 tax of 59 € with the reading used, 94 € with the other. On your data, the reading that makes you pay the most: currency, taxable exchanges.
• Basis of the €305 allowance i×The allowance applies to the sum of the year’s sale prices (French tax code, art. 150 VH bis, II-B). The form adds up prices net of fees (line 51); impots.gouv.fr speaks of the “gross annual amount of sales”. The gross amount crosses the threshold sooner: it is the cautious reading.
  Reading used: gross prices. Other reading: prices net of fees (line 218). This choice changes nothing for you in 2025 (tax difference, computed from known data: 0 €).

220 · Total acquisition price

12,550 €

221 · Initial capital fractions of earlier sales

2,115 €

222 · Balancing payments received in earlier exchanges

0 €

223 · Net total acquisition price

10,435 €

What you received in 2025 without buying it — staking, savings rewards and interest, airdrops, referral rewards — valued in euros on the day of each receipt. Crypto Master puts figures on it and does not decide: this is neither an amount to declare nor a tax, and the tax treatment of this income is not chosen for you (what the tax authority says is below).

Received in 2025: 51 € i×Each receipt is valued at the closing price of the day it happened (UTC day), converted at the same day’s euro/dollar rate — or at the price the exchange reported, when it reported one. A token pegged to the dollar is worth one dollar. These are the simulator’s own readings: these amounts are what its “value on the day received” reading adds to the acquisition price. A value that no price can give is called unknown, never counted as zero.

• ETH — 0.01932843 12 receipts 51 €

• The overall value is that of the portfolio Crypto Master knows. The law asks for all the household’s digital assets, wherever they are held: an unlinked account or another household member is missing from it.
• Assets are valued at the closing price of the day of the sale. The tax authority accepts a daily average quote; the close approximates it.
• The day of a sale, and so its year, is taken in universal time (UTC): a sale on 1 January before 1 am Paris time is filed under 31 December, so in the previous year. Check any sale made around the turn of the year.
• The portfolio is taken at the day’s close, corrected for trades and sales made after the sale; other movements of the same day (transfers, rewards) are taken at the close.
• A dollar-backed token (USDC, USDT…) with no price that day counts as one dollar.
• A lending receipt (Aave aToken, Compound cUSDCv3) with no price that day counts at the price of its underlying: it is worth it one for one. A vault share does not.
• Tokens received without being requested are left out of the overall value: no market quotes them.
• An exchange between digital assets, stablecoins included, is treated as tax-deferred. No guidance treats stablecoins separately: this is an interpretation.
• Purchase fees paid in euros or dollars are added to the acquisition price; fees paid in crypto are not. No text explicitly addresses these fees.
• A negative balance — an entry is missing from the history — worth less than €2 that day (at the day’s price, or at its upper bound) counts as zero in the overall value. Above that, or with no price or bound to judge it, it stays an unknown.
• Rewards (staking, interest, airdrops) enter at a zero acquisition price: the cautious choice, as no guidance settles it.
• Not simulated: the option for the progressive scale, the high-income contribution, NFTs (sales from 2026), sales by other household members.

Sources, consulted on 06/10/2026: French tax code, art. 150 VH bis; BOI-RPPM-PVBMC-30-20; form 2086 (2026); 2026 social security financing act, art. 12.