How to calculate crypto capital gains: four methods with worked examples

You sold some bitcoin, opened the export from your exchange, and it shows a profit figure. That number is almost never the one your tax office will use. The exchange sees only its own account and usually applies one generic cost rule. Your tax office applies its own rule, to everything you hold, in your own currency. HMRC says it plainly in its guidance on selling cryptoassets: exchange reports can be essential, but they are not tax calculations and do not track your pooled costs.

This lesson shows how to calculate crypto capital gains by hand, with the rules of four tax systems that most of our readers deal with: France, Italy, the United States and the United Kingdom. All four tax the same event, a disposal for more than it cost you. Where they part ways is the cost. France spreads one total purchase price over the whole portfolio. Italy takes the most recent purchases first (LIFO), as its tax agency reads the law. The US uses first in, first out by default, or the exact lots you name, wallet by wallet. The UK averages every token in a single blockchain that runs exactly as written when it is called, holding and moving funds according to its code, without an intermediary able to change the outcome.">smart contract holding reserves of two or more tokens, supplied by users, that a decentralized exchange uses to execute trades automatically at a price set by a formula.">pool, with two matching rules that come first.

Every example below uses hypothetical prices, and every figure has been worked out to the cent. If you need the general principles first (what counts as a taxable event, why holding is not taxed), start with our lesson on crypto tax basics. The rules are as of October 2026. This is an explainer, not tax advice: for your own return, a tax adviser in your country of residence has the last word.

One subtraction, four ways to pick the cost

Every crypto capital gain comes from the same line: what you received, minus the cost you are allowed to set against it. If the result is negative, it is a loss.

The first term rarely causes trouble. It is the price you got, in your own currency, on the date of the disposal. When you received something other than cash (another token, a laptop, a service), it is the market value of what you received on that date, converted at the rate of the day. The French tax administration (BOFiP), the Italian Agenzia delle Entrate, the IRS and HMRC all ask for that value in euros, dollars or pounds at the time of the trade, not at year end.

The second term is where the work is. Suppose you bought bitcoin three times at three prices and now sell part of it. Which purchase did you sell? Your tax office answers that question for you, and each of the four answers below gives a different gain on the same trades. Example B in the Italian section shows the spread: the same sale gives a gain of 6,000, 9,200 or 12,000 euros depending on the rule.

	France	Italy	United States	United Kingdom
Cost rule	Total purchase price of the whole portfolio, shared in proportion	LIFO per token (Agenzia circular 30/E, 2023)	FIFO by default, or lots you identify, per wallet or account	Section 104 pool per token, after same-day and 30-day matching
Crypto-to-crypto swap	Not taxed (deferred) without a cash top-up	Not taxed between cryptos with the same features	Taxable disposal	Taxable disposal
Trading fees	Sale fees reduce the sale price, on receipts	Not deductible	Added to cost on a buy, deducted on a sale	Allowable costs
Yearly relief	Exempt if total sale prices of the year are 305 euros or less	None for sales from 1 January 2025	None	3,000 pounds of gains (2025-26 and 2026-27)
Rate on the gain	12.8% income tax plus social levies (31.4% in total, see below)	26% for 2025 gains, 33% for gains from 2026 (euro e-money tokens 26%)	0%, 15% or 20% long-term (2025 brackets); ordinary rates short-term	18% or 24%

Sources for the table: BOFiP and notice 2086 (France), circular 30/E and laws 207/2024 and 199/2025 (Italy), IRS digital asset FAQ and Topic 409 (US), HMRC Cryptoassets Manual and gov.uk (UK), all read in October 2026.

How to calculate crypto capital gains in seven steps

Whatever your country, the work follows the same order. The country rule only enters at step 5. Most mistakes happen earlier, in a missing wallet or a forgotten swap.

1. List every place where you have held crypto since your first purchase: each exchange account, each app, each hardware or software wallet, each DeFi protocol. A wallet you no longer use still counts if it held coins during the period.
2. Export the complete history of each one, from the very first transaction rather than just the current year. Exchanges do not keep histories forever and some close accounts, so download a CSV file at least once a year. For a self-custody wallet, keep the address and the block explorer links of its transactions.
3. Put every operation in one sheet with its date, asset, quantity, counter-asset and fee, then value each one in your tax currency at its date. Note where each rate comes from (the exchange’s own price, or a price site with daily history).
4. Mark the operations that are easy to miss: crypto-to-crypto swaps, fees paid in crypto, payments for goods or services, transfers between your own wallets (not disposals in any of the four countries, but they must match up so a transfer is not counted as a purchase or a sale).
5. Apply your country’s cost rule to each disposal: the French portfolio formula, Italian LIFO, US FIFO or specific identification, or the UK matching rules and pool. The four sections below show the arithmetic.
6. Add up the gains and losses of the tax year. The tax year is the calendar year in France, Italy and the US, and 6 April to 5 April in the UK. Check the yearly relief of your country and what it does with losses.
7. Keep the file and the proofs behind it. A tax office can ask years later, and in France and Italy a purchase you cannot prove can be counted at a cost of zero.

If your coins sit on several platforms, our guide on how centralized exchanges hold your crypto explains why the exchange’s own records stop at its door, and why transfers in from elsewhere often show up with no purchase price at all.

France: one formula for the whole portfolio

The French method comes from article 150 VH bis of the tax code and is detailed in the BOFiP. Rates, the 305 euro threshold and the forms (2086, 3916-bis, line 3AN of the 2042 C) are explained in our lesson on crypto taxes in France. Here we only do the calculation.

France does not ask which coin you sold. It treats everything the household (foyer fiscal) holds as one portfolio, and each taxable sale uses up a share of the total price ever paid for it. The BOFiP formula is: gross gain = sale price minus (total acquisition price multiplied by sale price, divided by the global value of the portfolio).

The three inputs, in plain terms:

• The sale price is what you received in euros (or the euro value of the goods or service you paid for), minus the sale fees you can prove with receipts. A cash top-up received in a swap is added, one paid is subtracted.
• The total acquisition price is the sum of everything you have paid in money for all your crypto since the start, less the share of it already used by earlier taxable sales (the fractions of initial capital). Swaps that benefited from the deferral do not change it.
• The global value of the portfolio is the market value, just before the sale, of all the digital assets the household holds, on every exchange and in every wallet, including those abroad and offline. The BOFiP accepts prices from common sites with a daily average price history.

One detail changes the result. The fees reduce the sale price in the first term only. The fraction in brackets uses the sale price before fees. The BOFiP and the 2086 notice both state it.

Example A: two sales in one year

In January you buy bitcoin for 2,000 euros. In March you buy ether for 1,000 euros. Your total acquisition price is 3,000 euros, and you hold nothing else.

In October your portfolio is worth 5,000 euros (3,500 in bitcoin, 1,500 in ether). You sell part of the bitcoin for 1,250 euros and pay a platform fee of 10 euros.

• The share of the purchase price used by this sale is 3,000 × 1,250 / 5,000 = 750 euros.
• The gain is (1,250 − 10) − 750 = 490 euros. The fee comes off the 1,250 in the first term, not inside the fraction.
• The acquisition price left for later sales is 3,000 − 750 = 2,250 euros.

In December your portfolio is worth 4,200 euros. You sell crypto for 1,050 euros, with no fee.

• The share used is 2,250 × 1,050 / 4,200 = 562.50 euros.
• The gain is 1,050 − 562.50 = 487.50 euros.
• The acquisition price left is 2,250 − 562.50 = 1,687.50 euros.

Your sale prices for the year total 2,300 euros, above the 305 euro threshold, so every sale is taxed from the first euro. The net gain is 490 + 487.50 = 977.50 euros. Notice what did not enter the calculation: which coin you sold and what that coin cost. Sell ether instead of bitcoin for the same amount and the result is identical. A swap of ether into solana between the two sales would change nothing either, since it is deferred.

Now the rate. Income tax is 12.8%, or 125.12 euros here. Social levies come on top, and they changed with the 2026 social security budget. Law 2025-1403 of 30 December 2025 (article 12) raised the CSG on capital income from 9.2% to 10.6%, and for income taxed as revenus du patrimoine (article L. 136-6 of the social security code) it applies from the taxation of 2025 income. The BOFiP itself files crypto gains under the levies on revenus du patrimoine, and the only income of that kind the law keeps at 9.2% is rental income. On our reading, that puts the levies on crypto gains at 18.6% for gains made in 2025 and in 2026, for a total of 31.4%: 181.82 euros of levies, 306.94 euros in all for Example A. Under the old 17.2% the total would have been 293.25 euros. The question-and-answer page of impots.gouv.fr on digital assets, updated on 17 July 2026, does print a flat tax of 31.4% (12.8% tax plus 18.6% levies), without naming the income year. As of 24 October 2026 the BOFiP page on the rate still shows 17.2% and 30%, and the 2086 notice gives no levy rate, so check the figure on your tax notice (avis d’imposition). Losses offset gains of the same year only and cannot be carried forward.

Italy: documented cost, last in first out

In Italy a crypto gain is the difference between the price received (or the normal value of the crypto received in a taxable swap) and the documented cost of what you sold. Rates, the RT and RW sections of the return and the deadlines are in our lesson on crypto taxes in Italy.

The law does not say which units you sold when you bought the same token several times. The Agenzia delle Entrate filled the gap in its circular 30/E of 27 October 2023: for crypto with the same name, the cost is the one given by the LIFO method, last in, first out. The rule covers people who declare their own gains. If an Italian intermediary computes and pays the tax for you (the risparmio amministrato regime), it follows its own rules, so check its statement. The circular does not say whether LIFO runs across all your exchanges and wallets together or account by account; the natural reading is all units of that token you own, but it is not written down.

Two other Italian rules raise the gain. Purchase and sale fees cannot be deducted: the circular says the crypto provision does not allow it, unlike for shares. And a cost you cannot prove with precise documents counts as zero.

Example B: three purchases, one sale

You buy bitcoin three times: 0.5 BTC in February for 10,000 euros (20,000 per bitcoin), 0.3 BTC in June for 9,000 euros (30,000 per bitcoin) and 0.2 BTC in September for 8,000 euros (40,000 per bitcoin). You now hold 1 BTC that cost 27,000 euros. In December you sell 0.4 BTC for 20,000 euros.

• Under LIFO, the September lot goes first: 0.2 BTC costing 8,000 euros. The other 0.2 BTC comes from the June lot, at 30,000 per bitcoin: 6,000 euros.
• The cost is 14,000 euros and the gain 20,000 − 14,000 = 6,000 euros. Fees, if any, change nothing.
• You keep 0.5 BTC costing 10,000 euros and 0.1 BTC costing 3,000 euros: 13,000 euros in all, which is 27,000 − 14,000.

The same sale under other rules, for comparison only: FIFO would take 0.4 BTC from the February lot at 8,000 euros and give a gain of 12,000 euros; an average cost (27,000 × 0.4 = 10,800 euros) would give 9,200 euros. In a rising market LIFO uses the most expensive coins first, so the gain is lower now and the cheap coins wait for a later sale.

The rate depends on the year of the sale. For gains realised in 2025 it is 26%, with no 2,000 euro threshold any more: 1,560 euros on Example B. For gains realised from 1 January 2026 the rate is 33%, or 1,980 euros, except gains on euro-denominated e-money tokens, which stay at 26%. The 33% comes from law 207/2024 (article 1, paragraph 24), for gains realised from 1 January 2026; the euro-token exception was added by the budget law for 2026 (law 199/2025), which calls 33% the ordinary rate. If Normattiva shows paragraph 24 as repealed, look at the date: it stays in force for the whole of 2026 and gives way on 1 January 2027 to the new consolidated income tax code (legislative decree 117 of 19 June 2026), which moves the rules to new article numbers. 2026 gains are taxed under the current text, at 33%. Losses are netted against gains and, if reported in the return of the year they arise, can be carried forward for four years.

United States: FIFO or the lots you name, wallet by wallet

For the IRS, crypto is property. Your basis is what you paid in dollars, plus transaction costs such as exchange commissions and gas fees, and the fees of a sale reduce your proceeds (IRS digital asset FAQ). The question is which units you sold.

If you do nothing, the IRS applies first in, first out: units leave in the order they were acquired, counted within the same wallet or account. You can instead use specific identification: name the units you are selling in your books and records no later than the time of the sale, and for units held at a broker, from 2026 you tell the broker which units you are selling, by the time of the sale. Choosing the lots after the trade, when you already know the result, is not allowed.

Since 1 January 2025 this works wallet by wallet: the units sold from an exchange account are matched against the purchases in that account, not against coins sitting in a hardware wallet. Revenue Procedure 2024-28 let taxpayers make any reasonable allocation of their unused basis to each wallet or account as of 1 January 2025; if you had coins in several places at that date, that allocation is the starting point of every later calculation. Our guide to how crypto wallets work explains the difference between an exchange account and a wallet you control.

Example C: same sale, two legal answers

In one account you hold two ether lots: 1 ETH bought on 10 March 2024 for $2,800, and 1 ETH bought on 3 September 2025 for $3,600. On 20 October 2025 you sell 1 ETH for $4,000 and pay a $12 fee, so your proceeds are $3,988.

• Under FIFO the March 2024 lot is sold. The gain is $3,988 − $2,800 = $1,188, long-term because you held it more than one year. In the 15% bracket, the tax is $178.20.
• With specific identification of the September 2025 lot, recorded before the sale, the gain is $3,988 − $3,600 = $388, short-term (about seven weeks). In a 24% ordinary bracket, the tax is $93.12.

Neither choice is a loophole. The lot you keep carries the other basis: under specific identification, the $2,800 lot is still there, with a larger gain waiting for the day you sell it. What matters is that the identification exists before the trade and can be shown.

Holding periods start the day after you acquire. One year or less is short-term and taxed as ordinary income; more than a year is long-term. For tax year 2025 the IRS long-term rates are 0% up to $48,350 of taxable income for a single filer ($96,700 married filing jointly), 15% up to $533,400 ($600,050) and 20% above. Gains go on Form 8949 and Schedule D. Brokers now send Form 1099-DA, which reports gross proceeds; basis is required only for units acquired in that broker’s custody from 2026 on, so for older coins and coins transferred in, the basis is yours to compute.

United Kingdom: the pool and the two matching rules

HMRC treats each type of token as one pool, the section 104 pool, with a single pooled cost (HMRC Cryptoassets Manual, CRYPTO22200). When you sell, the cost is the pool’s average. Before the pool, two rules match the sale with other purchases: first, tokens of the same type bought on the same day; then tokens bought in the 30 days after the sale. Only what is left comes from the pool. NFTs are not pooled.

The 30-day rule is aimed at selling and buying straight back, to book a loss or use up the yearly allowance while keeping the same position. It does not cancel the sale. It changes the cost used.

Example D: pool first, then a repurchase within 30 days

On 12 June 2025 you buy 10 ETH for £20,000; on 3 August 2025, 5 ETH for £12,500. Your ETH pool holds 15 ETH with a pooled cost of £32,500. On 20 October 2025 you sell 6 ETH for £15,600 and pay a £30 fee.

With no repurchase, the cost is 6/15 of the pool: £13,000. The gain is £15,600 − £30 − £13,000 = £2,570, and the pool keeps 9 ETH costing £19,500.

Now say that on 5 November 2025, 16 days after the sale, you buy back 2 ETH for £4,400. Those 2 ETH are matched with the sale first:

• Matched part, 2 of the 6 ETH: proceeds £5,200, fee £10, cost £4,400, gain £790.
• Pool part, 4 ETH: proceeds £10,400, fee £20, cost 4/15 of £32,500, or £8,666.67; gain £1,713.33.
• Total gain £2,503.33 instead of £2,570. The pool now holds 11 ETH costing £23,833.33; the 2 repurchased ETH never enter it, because the matching used them up.

For the 2025-26 tax year the first £3,000 of total gains is tax-free (the same for 2026-27), and the rest is taxed at 18% or 24% depending on your income (gov.uk). Example D alone would stay under the allowance; any other gains of the year are added to it.

Crypto-to-crypto swaps: taxed in two countries, deferred in two

Swapping one token for another is where readers most often get caught, because no money reaches a bank account. Take one swap: 1 ETH that cost 2,000 for solana worth 3,000 on the day, with no fee and no cash.

Country	Tax at the swap?	Cost of the SOL received
France	No: swaps between digital assets without a cash top-up are deferred	No separate cost: the portfolio’s total acquisition price is unchanged
Italy	No, if both cryptos have the same features and functions (Agenzia circular 30/E)	2,000 euros, carried over from the ETH
United States	Yes: gain of $1,000	$3,000, holding period starts the next day
United Kingdom	Yes: gain of £1,000 if the pooled cost of that ETH is £2,000	£3,000 enters the SOL pool

The Italian circular’s own example: 20 BTC costing 2,000 euros in total, of which 5 BTC are swapped for 10 ETH. The 10 ETH take a cost of 500 euros (a quarter of 2,000) and no gain appears until they are sold for euros or swapped for something of a different kind. That ‘different kind’ matters. A swap into an e-money token, such as a euro or dollar stablecoin issued under MiCA, is a taxable realisation in Italy, and a swap into an NFT is too. In France, a swap becomes taxable as soon as cash changes hands with it, and paying for goods or a service with crypto is a taxable sale at the value of what you bought. Our lesson on what stablecoins are explains the difference between e-money tokens and other stablecoins.

Under US and UK rules every swap is two events in your records: the disposal of the token you gave, and the acquisition of the token you received at its market value. HMRC says each acquisition in a crypto-to-crypto trade comes with a disposal that must be computed. Ten swaps in a year mean ten gain calculations, even if you never cashed out.

Fees: platform, gas and fees paid in tokens

Fees look small, but over hundreds of trades they shift the gain by real money. Each country treats a platform fee or gas fee differently.

• France: the fees of a taxable sale (platform fees, miners’ fees) reduce the sale price if you can prove them, in the first term of the formula only. The fees of a deferred swap are deferred with it. When the fee is paid in crypto, the BOFiP accepts treating the sale and the fee as one single operation, so you do not compute a second gain.
• Italy: no deduction, neither on the purchase nor on the sale. The gain you declare is higher than the net profit your exchange shows.
• United States: costs of acquiring add to basis, costs of selling reduce proceeds. A fee paid in crypto is itself a disposal of that crypto. Fees for moving coins between your own wallets do not count as transaction costs at all.
• United Kingdom: transaction fees, including fees for getting a transaction onto the ledger, are allowable costs (CRYPTO22150). For a swap, the fee relates to both legs and can be split between them on a just and reasonable basis. A fee paid in tokens is a small disposal of those tokens as well as a cost of the main sale (CRYPTO22280).

The practical rule is the same everywhere: keep the fee as its own column in your sheet, in tokens and in your currency, rather than netting it into the price. You can always remove it later if your country ignores fees. You cannot rebuild it from memory.

Records to keep, country by country

The tax office will not accept ‘the exchange shows it’. What it accepts is a file you can explain line by line. For every operation keep the date and time, the asset and quantity, the value in your currency with the source of that price, the counter-asset, the fee, the platform or wallet address, and the reason (purchase, sale, swap, payment, transfer to yourself).

• France: proof of every purchase price (without it the acquisition value counts as zero), receipts for the fees you deduct, the value of your whole portfolio at each sale across all wallets, and a running table of the fractions of initial capital already used.
• Italy: the documented cost of each lot, ‘con elementi certi e precisi’ in the circular’s words, since an unproven cost is zero; the list of your purchases in date order for LIFO; your losses as declared in the year they arose, to carry them forward.
• United States: records sufficient to support what you report, in the IRS’s words: purchase and sale details, fair market values, transfers between wallets, the identification of the lots you sold, and your 1 January 2025 basis allocation if you made one.
• United Kingdom: for each pool, the token, the dates and quantities of disposals, the quantity left, the sterling values, bank statements, and the pooled cost before and after each disposal.

Crypto tax software and spreadsheets both work, but check the method before you trust the output: many tools default to FIFO or to an average cost, which is wrong in France, in Italy and in the UK. Keep your purchase confirmations too; our guide on how to buy crypto shows what a clean purchase trail looks like. Income from staking, mining or airdrops follows other rules and is left to a later lesson; so are DeFi positions.

Six mistakes that change the result

• Using the exchange’s profit figure. It covers one platform, often one method, and it does not know what you paid elsewhere.
• In France, looking for the purchase price of the coin you sold. The formula never uses it: only the total price paid and the portfolio value count.
• In France, valuing only the exchange account. Coins in a hardware wallet or on a foreign platform belong in the portfolio value, and leaving them out raises the gain.
• Mixing wallets in the US. Since 2025, FIFO and specific identification run within each wallet or account, not across all of them.
• Forgetting a swap. In the US and UK it is a taxable disposal; in Italy a swap into a stablecoin that is an e-money token is one too.
• Counting a transfer to yourself as a sale, or a transfer in from your own wallet as a new purchase with a fresh cost.

If you hold your own keys, those last two mistakes are the most common: the exchange sees coins leaving or arriving and cannot know they are still yours. Your sheet has to make the link.

Once you can calculate crypto capital gains with your own country’s rule, filing is the next step, and it depends on where you live. In France, the result of the formula goes on form 2086 and then line 3AN (gain) or 3BN (loss) of the 2042 C; in the US, on Form 8949 and Schedule D; in the UK, in the capital gains pages of Self Assessment. If you moved country, used DeFi or have years of trades, have the file checked by a tax adviser. In Italy the next date is close: gains realised in 2025 go in quadro RT of the Redditi PF return (or quadro T for 730 filers), due on 2 November 2026.