Why won't your crypto tax calculator reconcile your history?

A calculator assumes complete data

Koinly, Divly, Kryptoverotus.fi and other tax calculators are good tools when the history is clean: one or two exchanges, working transaction exports, no on-chain transactions. In that case a calculator is cheaper than a reconstruction service and is perfectly sufficient.

But a calculator doesn't know what it's missing. When a purchase is missing, it sees a sale without an acquisition. When a wallet is missing, your own transfer looks like a sale. The following causes come up again and again.

The eight most common causes

1. The exchange's transaction export is incomplete

An export doesn't always cover the full history or every asset type. Telltale sign: crypto is being sold even though it was never bought. Fix: download the export for the entire period and check that it covers all products (spot, earn, staking, card).

2. Your own wallets are missing

A withdrawal from an exchange to your own wallet looks like a sale or a disappearance in the calculator if the wallet hasn't been added. Telltale sign: a large "disposal" on the same day as a withdrawal. Fix: exchange withdrawal rows often include a transaction ID that lets you find the destination address on the chain.

3. You have more wallets than you remember

Following exchange withdrawals isn't always enough. Funds may have been moved on from a wallet to another wallet of your own that was never used with the exchange. Fix: follow the outgoing transfers from known wallets onward until every significant transfer has been identified.

4. Duplicate rows

Some exchange exports record the same transaction twice, for example in basket trades where a single purchase appears both as a whole and as its parts. Telltale sign: the balance is too high. Fix: identify the mirror rows and remove them from the calculation.

5. Staking and lock-ups are interpreted as sales

Locking assets into staking or another product may appear in the export as an outgoing transfer, which the calculator then interprets as a disposal. Fix: identify transfers within the product and treat them as transfers.

6. Small leftovers from swaps

Token-to-token swaps often leave small leftovers on the chain. If they aren't handled consistently, hundreds of swaps can end up recorded as extra sales.

7. Same ticker, different token

A chain can have several different tokens with the same symbol. If a token is identified by its ticker rather than its contract address, the acquisition costs of different assets get mixed up.

8. Block explorer exports get cut off

CSV exports from blockchain explorers are often cut off after a few thousand rows, and they don't always include changes in token balances. A large wallet has to be read directly from the chain.

Balance reconciliation – the only reliable test

Once every transaction has been processed, the remaining amount of each crypto asset according to the calculation must match what is actually in your wallets and on exchanges. If the calculation claims you have 26 SOL somewhere that holds nothing, a transfer has been misinterpreted. If the calculation goes negative, an acquisition is missing.

Without reconciliation, a calculation can look finished and still be wrong. Reconciliation is also what lets you justify the report to the Finnish Tax Administration (Verohallinto).

Example: what a mess looks like

In one history we reconstructed, the starting point was a single exchange export and a few remembered addresses. The result: 10 addresses of the client's own across four chains, more than 18 000 on-chain transactions and 7 655 disposals. The exchange export was incomplete, the basket trades contained mirror rows, and one of the largest wallets only turned up by following another wallet's outgoing transfers. No calculator would have found it, because it had never been entered.

Calculator or reconstruction?

In the diagnosis we'll tell you plainly if your history is clean enough for a calculator to do the job. In that case we won't sell you anything.