Reviewing your own calculation
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 6 min
In short
When the calculation is done, do not take the result at face value — check it from a few angles. Comparing closing balances against what you actually hold, sanity-checking transaction counts, and looking for outliers will surface missed imports and misclassifications. Take any difference you cannot resolve to a tax accountant.
Key points
- Matching closing balances against actual holdings is the strongest check
- Confirm the transaction count matches the data you collected
- Look for outsized gains or losses, and for rows with a zero cost basis
- Find the cause of any difference before correcting it
Definition
Cross-checking calculated results and closing balances against independent information to find errors.
The most effective check is the closing balance. Your calculation implies a quantity you should be holding at year end for each asset; compare that with the balances actually shown by the exchange or wallet. A match strongly suggests that asset's activity came through more or less completely. If the calculated balance is higher than reality, a disposal or transfer is missing; if lower, an acquisition or receipt is. The direction tells you where to look.
Next, check counts. Compare the total rows across your collected CSVs against the number of transactions the calculation actually ingested. This is where you catch a file that never loaded or a record type the tool ignored. Counts will not match exactly — deduplication alone sees to that — but a difference of an order of magnitude is a signal.
Third, look at outliers. Sort the result rows by amount and inspect both ends. You will sometimes find rows where the cost basis was treated as zero, so the entire sale proceeds became a gain, or rows that are simply off by a factor of ten. Zero-basis rows usually mean the record of how you acquired that asset never made it in, which makes them a useful thread to pull.
Fourth, look for gaps over time. Line up transaction counts by month: a month that is unusually sparse or empty often means that period's data never loaded, typically from a wrong date range on an export or a file that was split partway.
When you do find a difference, the principle is to identify the cause before correcting anything. Do not add a balancing entry to make the numbers agree. Once you know the cause, the proper fix is to re-obtain the correct data and recalculate. If a difference genuinely resists explanation, record what you investigated and take the treatment to a tax accountant.
Watch out for
- · This page is a general orientation, not tax advice
- · Do not paper over a difference with a balancing entry
- · How to treat an unresolved difference is case-specific — consult a tax accountant
Frequently asked questions
Is it abnormal if the closing balance does not match exactly?
Very small differences can come from lost precision or fee handling. Still, do not assume small means harmless — trace it at least once. If it stays unexplained, record what you did and ask a tax accountant.