UK Crypto Capital Gains Tax: Swaps, Stablecoins, Fees, Staking and Airdrops Explained

product-updatesguides

If you trade crypto on Binance, you already know the tax side is messy. Not because the rules are complex (HMRC treats crypto as property, CGT applies to disposals, done), but because the data is complex. Your export has swaps settled in USDT, fees paid in BNB, staking rewards mixed in with trades, and none of it is in GBP.

We've been building Binance support over the past few months, and along the way we wrote up how every piece of this actually works. The result is a new crypto section in our docs with worked examples and links to the HMRC Cryptoassets Manual. This post walks through the highlights.

Swaps are two events, not one

This is the thing that confuses people most. When you swap BTC for ETH on Binance, your trade history shows one line. But for tax purposes it's two transactions: you disposed of BTC (taxable) and acquired ETH (not taxable until you sell it). HMRC is explicit about this in CRYPTO22100.

Our calculator splits every swap into a sell and a buy automatically. So if you had 50 trades on Binance but 20 of them were token-to-token swaps, your CGT report will show 70 lines. That's not a bug. Each side needs its own matching against your Section 104 pool.

Fees on swaps go to the disposal side only. If we attached them to both sides, they'd be double-counted.

How are stablecoins taxed?

For pricing, we treat stablecoins as their fiat equivalent. A BTC/USDT trade is really BTC/USD. The USD amount then gets converted to GBP at HMRC's daily exchange rate.

We map USDT, USDC, BUSD, DAI and about 10 others to USD. AEUR and EURI map to EUR, GYEN to JPY. If a token isn't on our stablecoin list, it gets treated as a crypto-to-crypto swap instead, with both sides priced from market data.

The fee problem

Crypto trading fees are deductible (CRYPTO22280), but Binance makes this harder than it needs to be. Unlike a stock broker that charges a flat commission in your account currency, Binance fees can show up in three different forms:

If the fee is in the quote currency (say, USDT), it's straightforward. We convert it to GBP and deduct it.

If the fee is in the asset you're trading, it gets interesting. Say you sell 1 ETH and Binance charges 0.001 ETH as a fee. You've actually disposed of 1.001 ETH total, because those fee tokens left your wallet too. The disposal quantity goes up, which affects your pool calculation.

And if you're paying fees in BNB (Binance's discount programme), we need a BNB/GBP price for that day. If the price isn't available, the fee gets recorded as zero and you'll see a warning in your report.

Staking rewards and airdrops

These only come through if you upload a Binance Statements CSV alongside your trade history (see Supported Brokers for which exports to use).

Staking rewards, earn products, referral commissions and card cashback are all treated as miscellaneous income at the GBP value on the day you received them. They also go into your Section 104 pool at that value, so the cost basis is set from day one.

Airdrops are different. Unsolicited tokens don't count as income when you receive them (CRYPTO22500). They enter your pool at zero cost. You only pay tax when you eventually sell or swap them, and at that point the full proceeds are your gain.

Converting everything to GBP

Every disposal needs a sterling value. The path to get there depends on what the trading pair looks like:

  • BTC/GBP – already in pounds, nothing to do
  • ETH/USD or SOL/EUR – converted at HMRC's daily exchange rate
  • BTC/USDT – USDT is mapped to USD first, then converted to GBP
  • ETH/BTC – BTC is priced in GBP using daily data from CryptoCompare and CoinGecko, then multiplied by the trade amount

If we can't find a price for a given date, we check one day either side. If it's still missing, the transaction gets flagged with a warning so you know exactly which coin and date to check.

Share matching rules apply to crypto too

Same rules as stocks: Same Day first, then Bed & Breakfast (30 days), then Section 104 Pool. We covered this in detail in our Section 104 guide. The mechanics are identical for tokens.

Read the full docs

The crypto documentation goes deeper on each of these topics, with worked examples you can follow step by step. Every rule links back to the relevant HMRC manual page.

Sources