Fair market value (FMV): what it means for crypto tax

Fair market value is the price an asset would fetch on the open market at a given moment. FMV is used to value crypto received as income, and to value both sides of a crypto-to-crypto trade, converted to your local currency.

General information, not tax advice. Crypto tax rules differ by country and change over time, verify against your country's guidance or a qualified advisor.

An example

If you receive an airdrop when the token trades at 5, its FMV on receipt is 5 per token, which is both your income and your cost basis.

Why it matters for your tax

Every income receipt and every swap needs an FMV on its own date. Getting those valuations right, on the correct day, is what keeps income and later gains consistent.

CryptaTax handles this automatically across your wallets and exchanges, so the concept is applied consistently without you tracking it by hand. Try the crypto tax calculator →

Related terms

• Cost basis
• Airdrop
• Proceeds and gains

See the full crypto tax glossary for every term, or the crypto tax guides for how they fit together.

Fair market value (FMV): what it means for crypto tax

Definition in context

Fair market value (FMV) is the price that an asset would sell for on the open market between a willing buyer and seller. In crypto, FMV is typically determined by the price on a major exchange at the time of the transaction. It is used to value crypto received as income, such as mining rewards or airdrops, and to value both sides of a crypto-to-crypto trade.

Why it matters to crypto records

FMV is essential for calculating the value of transactions in your local currency. When you receive crypto as payment, you must include its FMV as income. When you trade one crypto for another, you need the FMV of both assets to determine the gain or loss. Using accurate FMV ensures correct tax reporting and avoids discrepancies.

Record example

You receive 0.1 BTC as payment for freelance work. On the day you receive it, the FMV of BTC is $30,000, so you have $3,000 of income. Later, you trade that 0.1 BTC for 2 ETH. At the time of the trade, the FMV of 0.1 BTC is $3,500, and the FMV of 2 ETH is also $3,500. You have a capital gain of $500 ($3,500 - $3,000) on the disposal of BTC, and your cost basis in the ETH is $3,500.

Distinctions and next steps

FMV is different from cost basis, which is what you paid. FMV is also different from the price you actually receive, which may be lower or higher. For volatile assets, FMV must be determined at the exact time of the transaction. To ensure accuracy, use a reliable price source and timestamp for each transaction. Keep records of the FMV used and the source. Consider using crypto tax software that automatically fetches historical prices.

A valuation note should identify the asset, valuation date and time, market or source consulted, quoted price, currency and any conversion used in the records. Where several venues show different prices, keep the selection rationale rather than silently replacing one figure with another. Illiquid assets, exchange outages and token migrations deserve an explicit exception note because a familiar ticker can conceal a different instrument or market. This is evidence discipline, not a universal valuation rule: the right source and timing can depend on the relevant reporting framework and facts.

A careful next step

Before acting on this term, return to the original record and write down the question it raises: what changed, which source proves it, and whether another related concept describes the event more accurately. Keep that note with the export or wallet evidence. It makes a later review faster and avoids turning a short label into an unsupported conclusion about tax, accounting or reporting.