Crypto tax
in plain English.
Import your transactions, see your taxable gain for free, download your SA108-compatible report for £49/year.
Private beta. Join the waitlist for founding member pricing.
Why this exists
Most crypto tax tools make you pay before they show you anything.
You do not know if you owe £0 or £5,000. You might be well under the annual allowance and have nothing to file at all. But to find out, you are expected to hand over £150 a year first.
That is backwards. We show you your taxable gain for free. If you owe nothing, you pay nothing. If you need the report to file your return, the Standard plan is £49 a year — cheaper than one hour with an accountant.
Why we built it this way →What you get for free
- Your exact taxable gain
- All tax years calculated
- Whether you are above or below the £3,000 allowance
- Your total gains, losses, and income
What the Standard plan adds (£49/yr)
- SA108-compatible PDF for all years
- Trade-by-trade breakdown
- Plain English notes for every figure
- Auto-recalculate as you add trades
The calculation
HMRC has three rules. They must be applied in order. Most people get this wrong.
Which purchase gets matched against which sale determines your gain. HMRC does not let you choose the most convenient match — it specifies an exact sequence. We apply it automatically.
Same-day rule
Applied first
If you buy and sell the same asset on the same day, those transactions are matched against each other before anything else. This prevents selling at the top, buying back the same day, and claiming the gain at a zero cost.
Example
Sell 1 BTC in the morning, buy 1 BTC in the afternoon — those two are matched first.
30-day rule
Applied second
If you sell and repurchase the same asset within 30 days, the sale is matched against the new purchase. Designed to stop "bed and breakfasting" — selling to crystallise a gain or loss and immediately rebuying.
Example
Sell on 1 March, rebuy on 15 March. The 15 March purchase is matched against the 1 March sale.
Share pool
Everything else
Any remaining sales are matched against your average cost across all units of that asset you have ever held. Every purchase you have ever made for that asset goes into one pool. Your cost basis is the average.
Example
Bought 1 BTC at £20k and 1 BTC at £40k. Average cost is £30k per BTC. Sell 1 BTC: your cost basis is £30k.
We apply all three rules, across all your assets, for every tax year in your history.
You import your transactions. We do the matching.
Who this is for
If you hold crypto in the UK, you probably need this.
The casual holder
“You bought some Bitcoin a few years ago. Maybe sold a bit. You have a nagging sense you should check whether you owe anything — but you have been putting it off.”
Import your transaction history in two minutes. See immediately whether you are above or below the allowance. If you are under £3,000 net gain, you likely do not need to do anything.
The active trader
“You trade regularly. Dozens, hundreds, maybe thousands of transactions across multiple exchanges. You know you have gains but working out the exact figure — with correct HMRC matching — feels impossible.”
Import via API or CSV. We apply same-day, 30-day, and share pool rules across every transaction automatically. Every disposal is matched correctly.
The DeFi user
“You stake, you farm, you move assets across chains. Each of those events may be taxable and HMRC's guidance on DeFi is complex. You are not sure what counts as a disposal and what counts as income.”
We categorise each transaction type correctly. Staking rewards as income. Swaps as disposals. Transfers between your own wallets as non-taxable. Reported separately on your return.
Free checker
Do I need to file a tax return for crypto?
Question 1 of 2
Did you sell, swap, or give away any cryptocurrency during the 2024/25 tax year (6 April 2024 to 5 April 2025)?
This checker gives general guidance only. It is not tax advice. When in doubt, speak to a qualified tax adviser or check HMRC's guidance at gov.uk.
What we handle
Every transaction type HMRC cares about.
We do not just track buys and sells. We understand the tax treatment of every type of crypto event — and report them to HMRC in the right category.
Buying and selling
Every purchase and sale is a potential disposal. We calculate the gain or loss on each one using the correct matching rule.
Crypto-to-crypto swaps
Trading one cryptocurrency for another is a disposal of the first asset and an acquisition of the second. HMRC treats this the same as a sale. We calculate it correctly.
Staking and mining rewards
Rewarded coins are treated as income at the GBP value on the date you receive them. When you later sell, only the growth since receipt is a capital gain.
Airdrops
Most airdrops are treated as income at receipt. We categorise them correctly and include them in your income total, separate from capital gains.
On-chain wallet transactions
Paste an Ethereum or Bitcoin address and we pull in your transaction history automatically, with historical GBP prices fetched for each event.
Transfers between your own wallets
Moving crypto between wallets you own is not a disposal and should not be taxed. We identify these and exclude them from your gain calculation.
Gifts and losses
Gifts to others (not your spouse) are disposals at market value. Lost or stolen coins may be treated as a loss. We handle both correctly.
Transaction fees
Fees paid when buying increase your cost basis. Fees paid when selling reduce your proceeds. Both reduce your gain. We include them automatically.
The Standard plan report
Everything you need to file your Self Assessment. Nothing you do not.
The report follows the structure of HMRC's SA108 Capital Gains Summary. The figures go where they need to go on your return. No interpretation required.
Summary page
Your total gains, total losses, net gain, annual allowance used, and taxable gain — with a plain English explanation of each.
Disposal-by-disposal breakdown
Every sale listed with date, asset, quantity, proceeds, cost basis, and gain or loss. Complete traceability.
Income section
Staking, mining, and airdrop income listed separately from capital gains — because HMRC wants them reported separately.
SA108 section references
Each figure is labelled with the box number on form SA108 so you know exactly where to put it.
UK Crypto Capital Gains Tax Report
Tax year 2024/25 · Generated by Polyconomic
No card needed to see your gain.
Pricing
See your gain free.
Pay only if you need the report.
You should not need to spend money just to understand your own tax position. So you do not.
Free
£0
No card. No catch.
- Import from any exchange
- See your taxable gain
- Current & previous tax year
- Check if below the allowance
- Up to 10,000 transactions
Standard
£49
Per year. Cancel any time.
- Everything in Free
- Full SA108-compatible PDF reports
- All tax years included
- Auto-recalculate on new trades
Pro
£99
Per year. For active traders.
- Everything in Standard
- Unlimited transactions
- Accountant sharing
- CSV export of all transactions
- Priority support
Find out what you owe.
Two minutes. Free to look.
Import your transactions, see your taxable gain, check whether you are above or below the allowance. No card required for any of that. Subscribe from £49/year only if you need the official report.
No card needed to see your gain. Standard from £49/year if you need the official report to file.