# Crypto gas fees and transaction costs: UK tax guide

Some crypto acquisition and disposal costs may be deductible, but a gas fee is not automatically allowable just because it appears on-chain. Paying a fee in crypto is also a disposal of that fee token. Identify the purpose, value and tax treatment of each charge.

## Key facts

## Which fees relate to buying or selling?

Separate a charge for acquiring or disposing of an asset from general portfolio, subscription or administrative expenses. The statutory allowable-cost rules govern CGT deductions. A tax-software subscription should not simply be deducted from capital gains without establishing a permitted basis. Keep invoices and exchange trade confirmations.

Source: [HMRC: allowable costs](https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22150)
## Gas paid in ETH creates a separate token disposal

If ETH worth £10 is used to pay a qualifying fee, record the disposal of that ETH as well as the underlying transaction. Its own matched acquisition cost may differ from £10. Do not subtract £10 twice from the principal trade because one export lists a net amount and another lists a separate fee.

Source: [HMRC: fees satisfied in tokens](https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22280)
## Worked reconciliation: gross proceeds versus net receipts

Suppose a trade confirmation shows £2,000 gross proceeds and a £10 selling charge, while a bank receipt is £1,990. Start with either gross proceeds and one allowable deduction, or a clearly reconciled net amount. Applying the £10 deduction again to £1,990 understates the gain. Token-paid fees also require the separate disposal calculation described above.
## Wallet transfers, failed transactions and approvals

Record the purpose of each fee: moving holdings, granting a token allowance, an unsuccessful trade or making a completed acquisition. These are not interchangeable. The chain confirms expenditure, but not necessarily an allowable deduction. Keep uncertain fees in a separate review category instead of applying a blanket software rule.
## Fee review before filing

Check the trading pair, fee asset and whether a CSV amount includes the charge.

- Keep quantity and GBP value for fees paid in tokens.

- Match the fee to an acquisition, disposal or other activity.

- Check whether the import already reduced proceeds.

- Preserve a reason for any disallowed or manually adjusted fee.

[Match the cost of the fee token](https://digital-assets.co.uk/tax/pooling-section-104-rules/)

[Download transaction records](https://digital-assets.co.uk/templates/)

## Visual explanation
A crypto fee has two questions
A. The expense: Is this cost allowable for the underlying transaction?
B. The payment: Did paying in tokens dispose of an asset with its own cost?
A fee can require a deductibility assessment and a separate token-disposal calculation. Avoid deducting the same cost twice.

## FAQs
### Are all Ethereum gas fees tax deductible?

No. Their purpose and the applicable allowable-cost rules matter. Preserve evidence rather than treating every network charge as deductible.
### Is paying a fee in crypto a disposal?

Yes. HMRC treats the tokens used to satisfy a fee as disposed of at market value; their allowable cost is determined under the normal matching rules.

## Sources

- [HMRC: allowable costs](https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22150)
- [HMRC: fees paid in tokens](https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22280)

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— Digital Assets UK (https://digital-assets.co.uk/tax/crypto-gas-fees-uk/), reviewed 2026-09-30. Source: https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto22150