NFT Tax in the UK — How HMRC Taxes Buying, Selling, and Minting NFTs

NFT tax in the UK catches most people off guard. Buying an NFT on OpenSea with ETH is a disposal of that ETH for Capital Gains Tax purposes — even though you never sold to fiat. Selling an NFT for crypto is a disposal of the NFT. Minting is an acquisition. HMRC treats every one of these as a taxable event.

The rules are less intuitive than most people expect, and if your crypto tax tool can't read NFT marketplace contracts like OpenSea's Seaport, it's probably getting the numbers wrong — missing disposals, double-counting, or creating phantom gains.

This guide covers how HMRC taxes NFT purchases, sales, mints, and royalties in the UK — with worked examples and a breakdown of what most tools miss.

Buying an NFT is a disposal of crypto

This is where most people trip up. When you buy an NFT on OpenSea for 0.5 ETH, you haven't just "spent" ETH — you've disposed of 0.5 ETH in exchange for an NFT.

HMRC treats crypto-to-crypto exchanges as disposals (CRYPTO22100). It doesn't matter that no fiat was involved. The ETH you spent had a cost basis in your Section 104 pool, and the market value of that ETH at the time of purchase is your disposal proceeds.

At the same time, you've acquired the NFT at a cost basis of £1,400 (the market value of the ETH you paid). If you later sell the NFT, that £1,400 becomes your allowable cost.

Selling an NFT is a disposal of the NFT

When you sell an NFT on OpenSea for ETH (or any other crypto), you are disposing of the NFT. The disposal proceeds are the market value of the crypto you receive, converted to GBP at the time of sale.

The gain or loss is calculated as:

• Proceeds = market value of crypto received (in GBP)
• Allowable cost = what you paid for the NFT (including gas fees)
• Gain/loss = proceeds minus allowable cost

Minting an NFT

Minting is the creation of a new NFT. From a tax perspective, there are two scenarios:

Free mint (gas only)

If you mint an NFT for free (only paying gas), you've acquired an asset at a cost basis of zero (plus any gas fees). There is no disposal of crypto beyond the gas payment. If you later sell this NFT, your entire sale proceeds (minus gas) are a capital gain.

Paid mint

If you mint by paying ETH (or another token) to a minting contract, this is a disposal of the crypto you paid — just like buying an NFT on a secondary marketplace. The crypto spent comes out of your S104 pool, and you recognise a gain or loss on it.

The minted NFT enters your portfolio at a cost basis equal to the GBP value of what you paid (plus gas fees).

OpenSea marketplace fees and creator royalties

When you sell an NFT on OpenSea, the marketplace takes a fee (2.5% on Seaport), and the creator may receive a royalty. The amount you actually receive is after these deductions.

For the seller: your disposal proceeds are what you actually receive — after marketplace fees and royalties. The fees reduce your taxable gain. Gas fees paid on the sale transaction are an additional allowable cost.

For creators receiving royalties: royalty income from NFT sales is likely taxable as miscellaneous income (or trading income if you create NFTs as a business). This is income tax, not CGT — reported on your SA100, not SA108.

NFTs received as airdrops or rewards

If you receive an NFT as an airdrop, reward, or prize, HMRC treats this as income at the fair market value on the date of receipt. This is consistent with how all crypto airdrops and rewards are treated (CRYPTO21200).

The challenge is valuation — unlike fungible tokens, NFTs don't have a readily available market price. HMRC expects a reasonable estimate of fair market value. If the NFT has no market value at the time of receipt (e.g. a POAP attendance token), the income value is effectively zero.

ChainTax classifies POAP mints as TRANSFER — non-taxable, zero cost basis — since they have no tradeable market value. For more on how HMRC treats different types of crypto income, see our guide to reporting staking rewards and DeFi income.

Why generic tax tools get NFT transactions wrong

NFT marketplace contracts are complex. OpenSea alone has gone through multiple contract versions:

• Wyvern v1 — the original OpenSea exchange (2018–2022)
• Seaport 1.5 — OpenSea's successor protocol
• Seaport 1.6 — latest version, multichain

Each uses different event signatures, different order structures, and different fee mechanisms. A tax tool that doesn't specifically parse these contracts will see generic token transfers and either:

1. Miss the NFT transaction entirely (classifying it as UNKNOWN)
2. Treat it as a simple ETH transfer (missing the disposal)
3. Double-count by treating both the NFT movement and the ETH payment as separate disposals

How ChainTax handles NFT transactions

ChainTax's classification engine includes dedicated handlers for NFT marketplaces:

The engine reads the OrderFulfilled event from Seaport contracts to determine whether you were the buyer or seller, what was paid, and in which token. For buyers, the crypto spent is recorded as a disposal. For sellers, the crypto received is recorded as proceeds.

Want to see how a specific NFT transaction is classified? Paste any transaction hash into the free transaction explainer and see the full breakdown.

Summary: NFT tax treatment in the UK