- UK rules, shown in full
- Private by design
- No account, no subscription
UK crypto tax calculator
Work out your Capital Gains Tax for any tax year from 2019/20, with HMRC’s same-day, 30-day and section 104 pool rules applied to every disposal — and shown, so you can check the working. Nothing leaves your device.
Drop your exchange exports here
CSV or Excel, several files at once, up to 20 MB each.
Coinbase, Kraken, Binance, Crypto.com, Revolut — or our universal CSV for anything else.
Free estimate, no account. Covers 2019/20 to 2026/27, including the 2024/25 mid-year rate change. Not tax advice — see the disclaimer.
- Gains
- £30,000
- Allowance
- £3,000
- Taxable
- £27,000
- Rates
- 18% / 24%
- Sold 0.5 BTC10 Jun 2025 · proceeds £45,000gain£13,500Same-day£2,00030-day£500Pool£11,000
- Swapped 0.3 BTC → ETH1 Aug 2025 · proceeds £27,000gain£16,500Pool£16,500
Why people use CryptoTaxCheck
10 Jun 2025 · 0.5 BTCgain £13,500
Same-day£2,00030-day£500Pool£11,000
UK rules, shown in full
Every disposal shows which HMRC rule matched it and the pool before and after. No black box — you or your accountant can check each line.
Everything that leaves your browser
{ "asset": "BTC", "date": "2025-06-10" }Private by design
Files are read in your browser and never uploaded. Only a coin symbol and a date are sent when a GBP price is missing — and a test in our build proves it.
- Free estimate
- £0
- Tax Year Report
- £29, once
- HMRC Letter Pack
- £59, once
No account, no subscription
See your gains, losses and estimated tax free. If you want the full PDF for your return or an HMRC letter, you pay once.
How it works
Three steps, about ten minutes if your exports are to hand
Progress is saved on your device, so you can come back to it. Start with files, or without them.
Add your exchange files
Download the transaction history from each exchange or wallet and drop the CSV or Excel files in — several at once is fine. They are read on your device and never uploaded.
We apply HMRC’s matching rules
Every disposal is matched in HMRC’s order: same-day purchases first, then purchases in the following 30 days, then your section 104 pool at average cost. You review transfers and fill any gaps.
See your estimate, then the report
Per tax year: disposals, proceeds, gains and losses, estimated Capital Gains Tax, crypto income and whether you must report. Pay once if you want the full PDF with the working.
Reads exports from Coinbase, Kraken, Binance, Crypto.com App and Revolut, plus a universal CSV template for everything else.
See the rules applied
Same-day, then 30-day, then the pool — for every disposal
HMRC does not let you pick which coins you sold. Its share-matching rules decide, in a fixed order, and the pool’s average cost does the rest. Here is one disposal from our worked example.
- 1Same-day rule. Coins bought on the day you sold are matched first.
- 230-day rule. Then coins bought in the 30 days after the sale — “bed and breakfasting”.
- 3Section 104 pool. The rest comes out of your pool at its average cost.
10 June 2025Sell 0.5 BTC for £45,000
HMRC matches the 0.5 BTC in this order
- Same-day ruleBought the same day, 10 June, for £16,000
- Proceeds
- £18,000
- Cost
- £16,000
- Gain
- £2,000
- 30-day ruleBought 25 June, within 30 days after the sale, for £8,500
- Proceeds
- £9,000
- Cost
- £8,500
- Gain
- £500
- Section 104 poolFrom the pool of 1.5 BTC at average cost (£52,500 ÷ 1.5)
- Proceeds
- £18,000
- Cost
- £7,000
- Gain
- £11,000
Total gain £13,500 — proceeds £45,000, allowable costs £31,500
Pool after: 1.3 BTC, £45,500. The 25 June purchase never enters it.
Had a letter from HMRC?
You have time to do this properly
An HMRC crypto letter, email or text is a prompt, not a penalty. Check it is genuine, work out which tax years it touches and reply through the right route — even if the answer is that you owe nothing.
- The letter helper turns seven questions into a personalised checklist and a deadline reminder.
- Back years to 2019/20, the 2024/25 mid-year rate change and a disclosure worksheet for the Cryptoasset Disclosure Service.
2025/26
81,172
crypto letters, emails and texts sent by HMRC — up from 64,982 the year before.
- 2023/24
- 27,714
- 2024/25
- 64,982
- 2025/26
- 81,172
The report
Every page, before you pay
The free estimate gives you the headline figures. The report adds the SA108 box values, a schedule of every disposal with its matching, the section 104 pool statement for each coin and the valuation method — the evidence HMRC expects you to keep.
Pages 2 and 5 of the 11-page sample, generated from our published worked example.
Pricing
The estimate is free. Pay once for the report you need.
Free estimate
£0no account, no card
- Import and review your files
- Gains, losses and tax per year
- Whether you need to report
Tax Year Report
£29one tax year, paid once
- SA108 boxes with the right numbers
- Every disposal with its matching
- Section 104 pool statements
HMRC Letter Pack
£59up to 6 tax years, paid once
- Everything in the Tax Year Report
- Disclosure worksheet per year
- Response checklist and CSV exports
No subscription and nothing is stored unless you buy a report. Full comparison, refund policy and pricing questions on the pricing page.
Common questions
Common questions about UK crypto tax
Do I have to pay tax on crypto in the UK?
How does HMRC calculate crypto gains?
How much Capital Gains Tax will I pay on crypto?
Is this calculator really free, and is my data safe?
What if I have had a letter from HMRC about crypto?
Which exchanges can I import from?
More detail in the guides: UK crypto tax explained, Capital Gains Tax on crypto and the section 104 pool.
Ready when you are
Start with your files. Nothing leaves your device.
Free estimate in about ten minutes. Come back to it whenever you like — progress is saved on your device until you clear it.