Accountants handling crypto clients face a specific problem: most tools were built for retail self-service users, not for professionals managing dozens of clients. The right tool needs to be HMRC-correct, multi-client capable, and priced in a way that keeps the engagement profitable.
What accountants actually need from a crypto tax tool
Consumer crypto tax tools optimise for onboarding speed and simple portfolios. Accountant-facing tools need different things: the ability to view client data without the client needing to be present, a clear audit trail explaining every calculation, SA108-compatible output that maps directly to filing boxes, and the ability to add manual transactions for over-the-counter deals, gifts, and inheritance events that never appear on an exchange. Pricing that scales reasonably across a client book is also essential — per-client fees that work at five clients become unworkable at fifty.
The five tools worth knowing
Polyconomic
See accountant plan →The accountant access model is built into the product rather than bolted on. Add a client by email, access their full portfolio and tax position directly, download the SA108-compatible PDF on their behalf. Because Polyconomic is UK-only, every calculation is done against HMRC rules — there is no country selector to misconfigure. Clients can grant access permanently so their tax position is always available without repeated exports. Pricing is per report rather than per client per year, which keeps costs proportionate to work done.
Koinly
Koinly offers a dedicated accountant plan that consolidates multiple client portfolios into a single dashboard. Integration coverage is broad — useful for clients with many exchanges. The subscription model means annual fees per client, which is a cost consideration at scale. Koinly supports UK HMRC rules and is probably the most widely recognised tool among UK crypto accountants after Polyconomic.
CryptoTaxCalculator
Particularly strong for clients with complex DeFi activity — multiple protocols, unusual transaction types, and on-chain categorisation challenges. The transaction detection logic is among the best in the market for on-chain activity. Accountant plans are available. The subscription model applies per client, which adds up for high-volume practices.
Blockpit
Better suited to practices with clients holding assets across multiple European jurisdictions alongside UK. If you have clients who are UK-resident but have German, Austrian, or Swiss tax obligations alongside their HMRC position, Blockpit handles multi-jurisdiction reporting more naturally than UK-only tools. Client management features are included in business plans.
TaxBit
Enterprise-focused and primarily US-built, TaxBit is used by some institutional-facing UK accountants dealing with corporate treasury clients, exchanges, or businesses with large-scale crypto holdings. It is not appropriate for an individual investor client base — the pricing and complexity are enterprise-tier. Worth knowing it exists, but not a recommendation for standard practice use.
The non-negotiable criteria
Before recommending any tool to clients, verify:
- ·HMRC matching rules (same-day, 30-day, Section 104) are applied correctly and in the right order
- ·The report output maps to SA108 boxes explicitly — not just a generic gains summary
- ·Manual transaction entry is supported for OTC purchases, gifts, inheritance, and lost assets
- ·Client data is isolated and cannot be accessed by other users accidentally
- ·An audit trail is available showing how each gain was calculated
Frequently asked questions
Can I add a client to Polyconomic on their behalf, or do they need to sign up themselves?
Clients sign up to Polyconomic and then grant accountant access by adding your email address. You receive an invitation to view their portfolio and can download reports from your own accountant dashboard without the client needing to be present.
What is the best tool for a client with a heavily DeFi-focused portfolio?
CryptoTaxCalculator has the strongest DeFi transaction detection on the market and is typically the best choice for clients with significant on-chain complexity. For simpler DeFi (standard staking, straightforward swaps), Polyconomic handles these correctly and may be sufficient.
Are there tools that can handle both HMRC and overseas tax obligations for expat clients?
Blockpit handles multiple European jurisdictions natively. Koinly supports a wide range of countries and may be appropriate for clients with US, Australian, or EU obligations alongside UK. For complex multi-jurisdiction situations, a specialist international tax adviser is often more appropriate than any software.
How should I handle a client who has no records from 2017 to 2020?
Incomplete historical records are a common problem. The options are: attempt to reconstruct from blockchain explorers for on-chain transactions, contact exchanges for historical CSV exports (many retain data going back several years), or use reasonable estimates with documented methodology. Any reconstruction should be clearly documented in case of enquiry.
Can crypto tax tools produce the HMRC capital gains computation format?
The best UK tools produce a PDF that maps directly to SA108 boxes and includes a disposal schedule. Polyconomic's report includes the section 104 pool workings, same-day and 30-day matches listed separately, and totals by tax year that correspond directly to SA108 input boxes.
What is the liability position for an accountant who uses a tool that produces incorrect figures?
As the preparer, you are responsible for the figures on the return regardless of the tool used. A tool is an aide, not a defence. You should satisfy yourself that the tool applies HMRC's rules correctly before relying on it for client returns, particularly for the matching rules where errors are most common.
Tool information accurate at time of writing.