Fix for when the cost basis in CryptoTax.be seems incorrect. Understand why the calculation differs and how to correct it for an accurate tax return.
My cost basis in CryptoTax.be does not seem correct
What is the problem
The cost basis that CryptoTax.be shows for a sale differs from what you expected. This can lead to an incorrect tax calculation.
Causes and solutions
Cause 1: Missing purchase transactions
If the purchase that belongs to a sale is not in CryptoTax.be, the tool cannot calculate the cost basis correctly. In that case the system may use the market price on a different date as an estimate, or it may show an error.
Solution: Check that all purchases have been imported. Missing transactions can be added via a CSV import or manually via Transactions > Add transaction.
the "Add transaction" button in the transaction overview
Cause 2: Transactions on the wrong exchange
If you bought a coin on exchange A but sold it on exchange B, and exchange A is not (fully) connected, CryptoTax.be is missing the purchase record.
Solution: Make sure all exchanges where you ever bought crypto are connected or imported as CSV.
Cause 3: Transfers are not labelled correctly
If you transferred coins from one exchange to another but that transfer was not marked as a "transfer", CryptoTax.be may interpret it as a sale and a purchase, which distorts the cost basis.
Solution: Go to Transactions, find the transfer, and change its type to Transfer (transfer between your own wallets).
editing a transaction and selecting the type "Transfer"
Cause 4: Difference due to the FIFO method
CryptoTax.be uses FIFO. If you calculated the cost basis yourself using a different method (e.g. average purchase price), the result will differ.
Solution: FIFO is the standard in Belgium. See How CryptoTax.be calculates the cost basis (FIFO) for more explanation.
Cause 5: Historical price data is missing
For less well-known coins or very old transactions, historical market prices may not be available.
Solution: See How to resolve missing historical price data.
How to edit a transaction manually
- Go to Transactions.
- Click on the transaction you want to edit.
- Click Edit.
- Adjust the amount, date, or price.
- Save.
Note: manual edits override the imported data. Document the reason for the edit for your own records.
