Tax on Cryptocurrency: UK and US Rules Explained
Buying, selling, and trading cryptocurrency can trigger UK Capital Gains Tax or US capital gains tax — and the rules differ depending on where you live and what you're doing with your crypto. Whether you're day-trading, HODLing, staking, or just swapping one coin for another, understanding when you owe tax is essential. This guide explains UK and US crypto tax rules in plain terms with worked examples so you know exactly when a crypto transaction becomes a taxable event and how much you might owe.
When Does Crypto Trigger a Tax Event?
In both the UK and US, simply owning cryptocurrency doesn't incur tax. You only pay tax when you dispose of it — that is, when you convert it to fiat currency (pounds or dollars), swap it for another crypto, or spend it to buy something.
A disposal event happens when you:
- Sell crypto for cash — selling 1 Bitcoin for £40,000 triggers CGT on any gain since you acquired it
- Swap one crypto for another — trading Ethereum for Bitcoin is a taxable event, even though no fiat changes hands
- Spend crypto to buy goods or services — paying for a coffee with Bitcoin creates a taxable gain equal to the difference between what you paid for the Bitcoin and its value on the purchase date
- Gift crypto — gifting is tax-free in the UK if the recipient is your spouse or civil partner, but gifting to anyone else is a disposal at market value
- Receive staking rewards or airdrops — these are taxable as income in the year received, not as capital gains (yet; rules are still evolving)
Simply buying crypto and holding it — even for years — is not taxable until you dispose of it. This is why the phrase "hodl" (hold on for dear life) appeals to tax-conscious investors.
UK Crypto Tax Rules
The UK treats cryptoassets as investments subject to Capital Gains Tax, not as currency. HMRC explicitly sets out this treatment in their guidance on tax on cryptoassets.
CGT Allowance and Rates
In the 2025/26 tax year, you have an annual capital gains allowance of £3,000. Any gains below this threshold are tax-free. Above £3,000, you pay CGT at:
- 20% if you're a basic rate taxpayer (£0–£50,270 of other income)
- 20% on gains (there is no higher rate for gains, unlike income tax)
Wait — that's a quirk worth noting. Capital gains are taxed at a flat 20% above your allowance, regardless of your income bracket. This makes capital gains more tax-efficient than salary above the higher rate threshold (40%). Someone earning £150,000 pays 45% income tax on additional earnings but only 20% on capital gains. This isn't a loophole; it's intentional policy to encourage investment.
Calculation example: You buy Bitcoin at £30,000 and sell at £35,000, making a £5,000 gain. Your first £3,000 is tax-free. You owe CGT on £2,000: £2,000 × 20% = £400 tax.
You must report capital gains to HMRC via Self Assessment if your total gains (including all sources) exceed £3,000 in a tax year. The tax year runs 6 April to 5 April, and you report by 31 January the following year. See our guide on tax year dates and deadlines for the full reporting calendar.
Staking and DeFi Income
Rewards from staking crypto or providing liquidity in DeFi are taxed as income (at your marginal rate: 0%, 20%, 40%, or 45%), not capital gains. This is less favorable than capital gains treatment because income tax has no annual allowance. [STAT NEEDED: confirmation of HMRC's current position on DeFi rewards, as this is still evolving].
Losses
If you sell crypto at a loss, you can offset that loss against capital gains in the same year or carry it forward indefinitely to offset future gains. You cannot use losses to offset income. Timing losses strategically — selling losers before year-end to offset winners — is a common tax-planning tactic called "tax loss harvesting."
US Crypto Tax Rules
The IRS treats virtual currency as property, not currency, with rules similar to stock trading. See the IRS FAQs on virtual currency transactions.
Capital Gains Rates and Holding Periods
Your tax rate depends on how long you held the crypto:
- Short-term gains (held ≤1 year): taxed as ordinary income at your federal tax bracket (10%–37%)
- Long-term gains (held >1 year): taxed at preferential rates of 0%, 15%, or 20%, depending on income
For 2025 (single filer), long-term capital gains are taxed at:
- 0% on gains up to ~$47,000
- 15% on gains $47,001–$518,900
- 20% on gains over $518,900
Long-term treatment is much more favorable. Holding for just over a year can save tens of thousands in tax. [STAT NEEDED: verify exact 2025 long-term capital gains thresholds].
Plus, you likely owe state capital gains tax (varies 0%–13.3% depending on your state), and 3.8% Net Investment Income Tax if your modified adjusted gross income exceeds $200,000 (single) or $250,000 (married).
Staking and Mining
Crypto received from staking or mining is taxed as ordinary income at fair market value on receipt. In the US, this can be significant — receiving £10,000 worth of staked rewards increases your taxable income by £10,000, taxed at your marginal rate. When you later sell that crypto, you then owe capital gains tax on any appreciation from the date received.
Reporting Requirements
You report crypto gains on Form 8949 (Sales of Capital Assets) and Schedule D. If you had over 200 transactions in a year, you may need to file Form 8453 to attach the full list. Exchanges like Coinbase and Kraken provide 1099-B forms summarizing your transactions, though accuracy varies.
How to Calculate Your Gain
The formula is simple:
Gain = Sale Price – Cost Basis
Cost basis is what you paid for the crypto plus any fees. If you bought 1 BTC for £30,000 plus a £50 exchange fee, your cost basis is £30,050. When you sell for £35,000, your gain is £35,000 – £30,050 = £4,950.
For swaps, cost basis applies to what you're giving up. Trading 1 ETH (valued at £2,000) for Alt Coin is a disposal of the ETH at £2,000, creating a taxable event.
Multiple Purchases and the Identification Rule
If you buy crypto multiple times at different prices, you need a method to identify which lot you're selling. UK tax law allows you to pick the most tax-efficient lot — typically the earliest purchase under the FIFO rule (First In, First Out), but you can elect to identify specific lots if it saves tax. The US allows the same, plus weighted-average and specific ID methods. Keep detailed records.
Example: You buy Bitcoin three times:
- January: 1 BTC at £20,000
- March: 1 BTC at £25,000
- September: 1 BTC at £28,000
You sell 1 BTC in December for £40,000. Using FIFO, you sell the January lot: gain = £40,000 – £20,000 = £20,000 (in the UK, you'd owe 20% × (£20,000 – £3,000 allowance) = £3,400 CGT). If you could identify the September lot, your gain would only be £12,000 — but most crypto platforms don't allow you to pick; they go by FIFO by default. Record your intent clearly.
Record-Keeping and Reporting
Both HMRC and the IRS expect detailed records. For UK tax purposes, keep:
- Purchase date, price, and quantity of each crypto acquisition
- Sale/disposal date, price, and quantity
- Any fees paid
- Proof of the fair market value on each transaction date
HMRC can enquire up to 4 years after the tax year (6 years if they suspect carelessness). The IRS can look back 3 years under normal circumstances, or 6 years if you underreported income by 25%.
If you're in both jurisdictions — a US citizen with UK tax residency, for instance — you may owe tax to both. See our post on US vs UK tax system differences for how to avoid double taxation.
Frequently Asked Questions
Q: If I buy crypto and hold it for 5 years without selling, do I owe tax?
A: No. Tax is only owed when you dispose of the crypto (sell, swap, or spend it). Simply hodling is not a taxable event in either the UK or US. Your unrealised gains are not taxed.
Q: What if I swap one cryptocurrency for another? Is that a taxable event?
A: Yes, in both jurisdictions. Swapping Ethereum for Bitcoin is treated as a disposal of the Ethereum at its fair market value on the swap date, triggering a capital gain or loss. Even though you never touched fiat currency, tax is due.
Q: How do I value crypto on the date of a transaction if I don't have a receipt?
A: Use the closing price on a major exchange (CoinMarketCap, CoinGecko) on the transaction date. Major exchanges like Kraken and Coinbase record the price at execution, so check your trade history. Be consistent — don't pick the lowest price you can find. HMRC and the IRS expect reasonable market values.
Q: Do I have to report every single trade?
A: In the UK, you report trades via Self Assessment once gains exceed £3,000. You don't need to list every single transaction on your tax return; you can summarize. However, you must keep detailed records in case of an enquiry. In the US, you must report every transaction on Form 8949, though the IRS's matching of broker 1099-Bs is improving — they're now checking exchange records more closely, so omitting trades is risky.
Q: What's the difference between the UK capital gains allowance and the US?
A: The UK offers a simple annual allowance of £3,000 per person (£6,000 for married couples filing jointly in most cases). The US has no annual allowance for capital gains, but has preferential rates for long-term gains (0%, 15%, 20%) vs. short-term (ordinary income rates). The US system rewards holding, the UK system allows a small amount free.
Q: If I received crypto as a gift, do I owe tax?
A: In the UK, receiving a gift is not taxable. However, when you dispose of it, you owe CGT on the gain from the date you received it. Your cost basis is the fair market value on the receipt date. In the US, gifts are not taxable either, but you inherit the donor's cost basis (a concept called "carryover basis"), so you may owe capital gains tax on gains built up by the person who gave it to you.
Q: Can I deduct losses from other income, or only from other capital gains?
A: In the UK and US, capital losses can only offset capital gains, not ordinary income. If you have £5,000 in capital losses but no capital gains, you cannot use them to reduce your salary. You can carry losses forward to offset future gains indefinitely.
Q: What if I'm mining or staking crypto?
A: Rewards are taxed as income (in your marginal tax bracket) at fair market value on receipt. In the UK, this is taxable from the moment you receive the reward. In the US, you owe income tax on the receipt date, then capital gains tax later if you sell the crypto for more than you received it. This is why US staking can be inefficient — you're paying income tax on the reward, then capital gains tax on appreciation.
Next Steps
Tax on crypto doesn't have to be complicated, but it does require careful record-keeping. Keep receipts of every buy, sell, and swap. If you have large holdings or frequent trading, consider using a tax-tracking tool (Koinly, CryptoTaxCalculator, or your exchange's built-in tax reports) to automate the calculation. For UK Self Assessment, our guides on UK tax-free allowances and National Insurance contributions explain other tax-efficient strategies that work alongside crypto gains.