To report crypto on your 2025/26 UK Self Assessment, enter disposals such as sales, swaps and purchases made with crypto in the Cryptoassets section of SA108, and declare mining, staking and other crypto income on SA100 or the relevant supplementary pages. HMRC expects both sides to be calculated in pounds and supported by your transaction history.
Finbooks brings your exchanges and wallets into one UK tax calculation, applies HMRC’s matching rules and prepares the figures needed for SA100 and SA108. This guide shows where those figures go, how to check them and what changed from the 2024/25 return.
What you need to know for 2025/26
The 2025/26 tax year ran from 6 April 2025 to 5 April 2026; the online filing and payment deadline is 31 January 2027.
Crypto disposals are reported separately from crypto income. The same transaction history can therefore feed both SA108 and SA100.
The paper SA108 uses boxes 13.1 to 13.8 for cryptoassets; HMRC Online asks for the equivalent totals in its Cryptoassets section.
The one-off split around 30 October 2024 does not apply to 2025/26. Box 51 only needs separate consideration where another CGT adjustment is genuinely required.
A complete calculation may need transactions from earlier years because pooled acquisition costs carry forward until the crypto is disposed of.
What crypto activity goes on SA100 and SA108?
SA108 records capital gains and allowable losses arising from crypto disposals. SA100 and its supplementary pages deal with taxable income, so the route depends on what you did and why you received the crypto rather than on the name used by the platform.
| Crypto activity | Typical UK tax treatment | Usual reporting route |
|---|---|---|
| Sell crypto for pounds | A disposal producing a capital gain or allowable loss. | SA108 Cryptoassets section. |
| Swap one token for another | A disposal of the token given up, even when no pounds reach your bank account. | SA108 Cryptoassets section. |
| Spend/give crypto to someone other than your spouse/civil partner | Normally a disposal at market value. | SA108 Cryptoassets section. |
| Receive staking, mining or similar rewards outside a trade | May create miscellaneous income when received; a later disposal can create a separate capital gain or loss. | Usually SA100 for the income and SA108 for the later disposal. |
| Receive tokens through employment | Employment income, with a separate capital calculation if the tokens are later disposed of. | Employment pages and, on disposal, SA108. |
| Carry on a crypto trade | Trading profits fall under Income Tax rather than the ordinary investor CGT treatment. | Self-employment pages. |
| Move crypto between wallets you beneficially own | Normally not a disposal, although fees paid in crypto may need separate treatment. | Not reported as a transfer; retain the evidence linking both sides. |
A platform label does not settle the tax treatment
“Rewards”, “earn”, “yield” and “airdrop” can describe very different arrangements. Some receipts are taxable income, some are capital from the outset and DeFi transactions can involve a disposal before any return is received. Review the transaction and the rights you gave up rather than relying on the label in the app.
When do you need to report crypto gains or losses?
You must complete the SA108 capital gains pages for 2025/26 if your chargeable gains before losses exceed the £3,000 Annual Exempt Amount, the crypto you disposed of was worth more than £50,000, or you want to claim an allowable loss. A return may also be required for other income or gains even when your crypto position alone falls below those figures.
If this is the first year in which you need Self Assessment, you would normally tell HMRC by 5 October 2026. Paper returns are normally due by 31 October 2026, while an online return and the tax owed are due by 31 January 2027.
A £3,000 exemption is not a £3,000 proceeds threshold
The Annual Exempt Amount is applied to net chargeable gains after the calculation, not to the value of crypto sold. You still need the proceeds, allowable costs and losses before you can decide whether any gain remains taxable.
How do you report crypto on your 2025/26 Self Assessment?
To complete Self Assessment for crypto, calculate your annual disposal and income totals in pounds, activate the Capital Gains Tax section in HMRC Online, enter the totals in the SA108 Cryptoassets section and declare crypto income in the matching income section. The work starts before you log in: consolidate the history, classify the activity and resolve gaps first.
Prepare the figures in Finbooks
- 1
Import the complete history: connect every exchange and wallet used during 2025/26, together with earlier transactions that still affect the cost of assets you held or sold.
- 2
Reconcile transfers and missing data: check unmatched movements, missing prices and negative balances so transfers between your own wallets are not mistaken for disposals.
- 3
Review income classifications: confirm how staking, mining, airdrops and DeFi receipts were earned instead of treating every incoming token in the same way.
- 4
Generate the 2025/26 SA Summary: Finbooks applies HMRC’s same-day, 30-day and Section 104 pooling rules, converts relevant amounts into pounds and separates gains, losses and taxable income.
- 5
Keep the supporting reports: the summary provides the totals for the return, while the transaction and disposal reports preserve the calculation behind them.
Activate the relevant parts of your HMRC return
In HMRC Online, the capital gains and income sections appear after you answer the questions in Tailor your return. Select the option confirming that you disposed of chargeable assets if you need the Capital Gains Tax section and its Cryptoassets entries.
If your Finbooks report contains taxable crypto income, activate the relevant income section as well. Miscellaneous income, self-employment income and employment income do not share a single universal crypto box, so choose the route that matches the source of the receipt.
Complete the SA108 Cryptoassets section
To complete the SA108 Cryptoassets section for 2025/26, enter the number of disposals, proceeds, allowable costs, gains and losses in boxes 13.1 to 13.5, and use 13.6 to 13.8 only for claims, elections or disposals already reported through the Real Time Transaction service. HMRC Online asks for the same totals through labelled questions.
| SA108 field | What HMRC asks for | What to use |
|---|---|---|
| 13.1 | Number of disposals. | Total crypto disposals in your Finbooks SA Summary. |
| 13.2 | Disposal proceeds. | Total sterling proceeds from reportable crypto disposals. |
| 13.3 | Allowable costs, including acquisition cost. | Total allowable costs calculated under HMRC’s matching and pooling rules. |
| 13.4 | Gains in the year before losses. | Aggregate gains before deducting current-year or brought-forward losses. |
| 13.5 | Losses in the year. | Aggregate allowable crypto losses arising during 2025/26. |
| 13.6 | Claim or election code. | Complete only where you are making a relevant claim or election. |
| 13.7 | Gains or losses already reported through the Real Time Transaction service. | Complete only if you used that service for the same disposals. |
| 13.8 | Tax already paid on the amount in 13.7. | Complete only where tax was paid through that earlier report. |
HMRC also asks for the computations supporting the totals. Your disposal report should allow each annual figure to be traced back to the relevant transactions, sterling valuations and matching rules rather than presenting only a single unexplained gain.
Report crypto income in the correct income section
If crypto receipts amount to miscellaneous income and the activity is not a trade, the total will commonly be entered as other UK income on SA100. A genuine trade belongs on the self-employment pages, while tokens received through employment follow the employment income rules.
The sterling market value recognised as income will generally form part of the acquisition cost when those tokens are later disposed of. Recording the receipt and the later disposal separately prevents the same economic value from being taxed twice.
What should you check before submitting your crypto return?
A correct set of totals should reconcile with the history behind it. Before submitting, work back from the return to the exchanges and wallets and make sure the calculation still accounts for every platform, transfer and taxable receipt.
Your final 2025/26 crypto filing check
Every exchange and wallet used during the year is included.
Earlier acquisitions feeding the Section 104 pools have not been omitted.
Transfers between your own wallets have been matched rather than treated as sales.
Transactions and income have been valued in pounds at the relevant time.
Income receipts have not been entered again as disposals unless there was a separate later sale, swap or spend.
Allowable losses, including any valid losses brought forward, have been considered.
The totals in SA100 and SA108 agree with the final Finbooks SA Summary.
You have retained the summary, disposal calculation and source records supporting the return.
Once the figures agree, complete HMRC’s declaration and submit the return. Save the submission receipt alongside your Finbooks reports and original platform exports so the final return remains connected to its audit trail.
Filing or amending 2024/25? When Box 51 matters
This section applies to 2024/25, not the current 2025/26 filing
This applies only to 2024/25 returns: because the main CGT rates changed on 30 October 2024, some taxpayers had to calculate a Box 51 adjustment by separating gains realised before and after that date.
For a 2024/25 return, Finbooks separates the relevant gains on either side of 30 October 2024. Those crypto figures must be considered together with any non-crypto gains, losses and reliefs before using HMRC's 2024/25 CGT Adjustment calculator.
For a 2024/25 return, Finbooks separates the relevant gains on either side of 30 October 2024. Those crypto figures must be considered together with any non-crypto gains, losses and reliefs before using HMRC’s 2024/25 CGT Adjustment calculator.
The calculator’s output, rather than the taxable gain itself, is the figure entered in Box 51. It is therefore normal for Box 51 not to match the gain shown in the SA Summary.
The 2025/26 return still contains a general Box 51 for CGT adjustments, but the pre- and post-30 October calculation does not carry into 2025/26 because the ordinary 18% and 24% rates apply throughout the tax year.
Bring your complete investment tax position together with Finbooks
Finbooks gives you the calculation behind the return as well as the figures that go into it, keeping crypto income, disposals, allowable costs and losses connected to the underlying exchange and wallet history.
If you also hold shares, ETFs or other investments, those accounts still form part of the same UK tax position. Our guide to reporting investments on your 2025/26 UK Self Assessment will show how dividends, interest and TradFi disposals fit alongside the crypto figures prepared here.
Crypto Self Assessment questions
Calculate your crypto disposals and income for the tax year in pounds, then enter the disposal totals in the SA108 Cryptoassets section (boxes 13.1 to 13.8) and the income in the matching section of SA100. For 2025/26, the online return and any tax due must reach HMRC by 31 January 2027.
Not necessarily, but the gain is only one part of the test. Reporting may still be required if your total disposal proceeds exceed £50,000, you want to claim a loss, you have taxable crypto income or another part of your Self Assessment requires the information.
Enter the annual totals in the Cryptoassets section of SA108, shown as boxes 13.1 to 13.8 on the 2025/26 paper form. HMRC Online presents the equivalent entries within its Capital Gains Tax section.
Staking and mining receipts outside a trade are commonly reported as miscellaneous income through SA100, while trading or employment activity uses the relevant supplementary pages. A later sale or swap of the tokens can create a separate capital gain or loss for SA108.
Allowable crypto losses can reduce gains from the same year, and unused losses can generally be carried forward after they have been claimed with HMRC. Include the loss in Self Assessment or notify HMRC within the applicable four-year claim period.
Not for the one-off rate split used in 2024/25. Box 51 remains available for other CGT adjustments, but an ordinary 2025/26 crypto calculation does not need to separate gains around 30 October 2024.