Cryptocurrency Capital Gains Tax Calculator 2025/26 — UK HMRC Rules
HMRC treats cryptocurrency as a capital asset — not currency. Every disposal (sale, swap, gift, or using crypto to buy goods) is a potentially taxable event. Calculate your CGT liability and annual exempt amount for 2025/26.
Cryptocurrency Tax UK 2025 — HMRC Rules and CGT Explained
HMRC treats cryptocurrency as a capital asset, not as money or currency. This means buying, selling, gifting, or exchanging cryptocurrency is subject to Capital Gains Tax (CGT). Every transaction involving crypto can potentially be a taxable event, and HMRC has progressively tightened enforcement — including data sharing agreements with UK exchanges and cross-border reporting under the OECD Cryptoasset Reporting Framework (CARF).
What Counts as a Taxable Disposal
A disposal includes any of the following:
- Selling cryptocurrency for sterling or other fiat currency
- Exchanging one cryptocurrency for another (e.g., Bitcoin for Ethereum)
- Using cryptocurrency to purchase goods or services
- Gifting cryptocurrency to anyone other than a spouse or civil partner
- Receiving cryptocurrency in exchange for providing services (also creates income tax liability)
Simply holding (HODLing) cryptocurrency is not a taxable event. Tax arises only on disposal.
Annual CGT Allowance and Rates
The CGT annual exempt amount is £3,000 for 2025/26. Gains within this allowance are tax-free. Gains above the allowance are taxed at:
- Basic rate taxpayers: 18% on crypto gains (from April 2024; previously 10%)
- Higher/additional rate taxpayers: 24% on crypto gains (from April 2024; previously 20%)
Report all gains over £50,000 in proceeds on your Self Assessment return, even if the gain itself falls within the annual allowance. Losses can also be reported to carry forward against future gains.
The Section 104 Pool — Cost Basis Calculation
HMRC requires the Section 104 pool method for calculating cost basis. Each time you buy a cryptocurrency, the cost is added to the pool for that asset. When you sell, the average cost per coin across the entire pool is used — not specific identification (FIFO or LIFO). The "same day rule" and "30-day bed and breakfasting rule" override pool calculations for purchases made on the same day or within 30 days of a sale — preventing artificial loss creation.
Staking, Mining, and DeFi Income
Staking rewards and mining income are typically treated as miscellaneous income, taxable at your marginal income tax rate in the year received, based on the sterling market value at the date of receipt. When those rewards are later sold, any increase in value from receipt to disposal is subject to CGT as well — creating a double taxation effect. DeFi activities (liquidity pools, yield farming, lending protocols) may create taxable disposals at each step — HMRC treats most DeFi transactions case by case and the area remains complex.
HMRC Compliance and Enforcement
HMRC requires UK exchanges to report customer transaction data, and from 2024 the OECD Cryptoasset Reporting Framework enables cross-border information sharing on crypto holdings. Penalties for deliberate non-disclosure can reach 100% of unpaid tax plus interest, and HMRC can investigate up to 20 years back for deliberate errors. If you have undeclared crypto gains from previous years, the HMRC Cryptoassets Disclosure Service enables voluntary disclosure with significantly lower penalties than being discovered through HMRC's data analysis.
NFTs, Airdrops, and Hard Forks
NFTs are treated as cryptoassets for CGT purposes. Airdrops are generally taxable as miscellaneous income at receipt value. Hard forks (receiving new coins when a blockchain splits) are treated as a new acquisition at nil cost — any gain on disposal is therefore fully taxable as CGT. Always keep records of all these events including the sterling value at the date of receipt.
Loss Relief — Using Crypto Losses to Reduce Your Tax Bill
Capital losses from cryptocurrency disposals can be offset against capital gains from any other source — not just crypto gains. If you made £10,000 profit selling shares but lost £4,000 on cryptocurrency in the same tax year, your net gain is £6,000 (within the £3,000 annual exempt amount after offsetting, you would owe tax on only £3,000). Unused capital losses can be carried forward indefinitely to future tax years — always report losses to HMRC even in years when no tax is owed, as the carried-forward losses reduce future liability.
HMRC's approach to cryptocurrency taxation continues to develop as the technology evolves. The HMRC Cryptoassets Manual (published at gov.uk/hmrc-internal-manuals/cryptoassets-manual) is regularly updated and provides HMRC's current interpretation of how tax law applies to specific crypto activities. Consulting the manual before complex transactions — particularly in DeFi, staking, or new token structures — is advisable. Where the tax treatment is genuinely unclear, a professional opinion from a tax adviser familiar with crypto may be worth obtaining before the transaction rather than dealing with uncertainty at filing time.
The most important practical advice for UK cryptocurrency investors is to use dedicated crypto tax software integrated with your exchange accounts from the beginning of your investing activity — not retrospectively when HMRC enquires. Software that automatically imports transaction history, calculates the Section 104 pool, applies the same-day and 30-day rules, and generates a CGT summary report saves enormous time and reduces the risk of errors that could result in penalties. The cost of good crypto tax software (typically £30–£150 per year) is a small fraction of the potential penalties for an inaccurate return on a portfolio of meaningful size.