Mistake 1: Treating transfers as sells
When you move crypto from Coinbase to MetaMask, that's a transfer, not a sale. No taxable event. But if your tax software doesn't recognize it as a transfer, it might record a sell on one side and a buy on the other, creating a phantom gain.
How to fix: Make sure every transfer between your own wallets is classified as a transfer, not a sell/buy pair. In CryptoTaxPilot, transfers between connected wallets are auto-detected. For manual CSV imports, check for large "sells" that match "buys" on another platform on the same day.
Mistake 2: Using FIFO when HIFO saves you more
Most exchanges and tax software default to FIFO (First In, First Out), which sells your oldest, cheapest coins first. For portfolios where crypto has appreciated over time, this maximizes your taxable gains.
HIFO (Highest In, First Out) sells the coins you paid the most for, minimizing your gain. Through 2026, the IRS explicitly allows you to use any method on your own records.
How to fix: Compare FIFO vs HIFO before you file. CryptoTaxPilot runs both automatically and shows you the exact dollar difference.
Mistake 3: Forgetting about staking and airdrop income
Staking rewards and airdrops are taxed as ordinary income at the fair market value when you receive them. A lot of people track their sells but forget to report the 200 micro-transactions of staking rewards they accumulated over the year.
How to fix: Import your full transaction history, including rewards. Your exchange CSV should include these. If you're staking on-chain, make sure your wallet scanner picks up reward transactions.
Mistake 4: Not reporting small transactions
"I only made $50 on a swap, do I need to report it?" Yes. Every disposal is reportable regardless of size. The IRS doesn't have a minimum threshold for capital gains reporting. Missing a bunch of small transactions can add up to a meaningful discrepancy.
How to fix: Import everything. Don't cherry-pick which transactions to include.
Mistake 5: Using exchange numbers instead of your own records
Your exchange only knows about transactions that happened on that exchange. If you transferred crypto in from another platform, the exchange doesn't know your cost basis. It might report $0 basis on the 1099-DA, making it look like your entire sale is a gain.
How to fix: Use tax software that aggregates all your sources. Your complete transaction history across all exchanges and wallets is the accurate picture. When the exchange's 1099-DA disagrees, use the adjustment column on Form 8949.
Mistake 6: Double-counting transactions
If you import a CSV from Coinbase AND connect the Coinbase API, you might get every transaction twice. Or if you import transactions from multiple exports that overlap in date range. Double-counted buys inflate your cost basis. Double-counted sells create phantom gains.
How to fix: Check your transaction count after importing. If it seems high, look for duplicates. CryptoTaxPilot automatically detects and skips duplicate transactions during import.
Mistake 7: Not keeping records for future years
Your 2025 tax return establishes which lots you sold and which you're still holding. In 2026 and beyond, your cost basis calculations depend on getting the prior year right. If you lose your records, you can't reconstruct which lots remain.
How to fix: Keep your tax software data year over year. Download your Form 8949 and full transaction export as backups. When 1099-DAs arrive in 2027, you'll need your historical lot data to reconcile.
The common thread
Most of these mistakes come from incomplete data. Missing an exchange, missing transfers, missing rewards. The fix is always the same: import everything into one place, verify the transaction count makes sense, and let the software handle the math.
CryptoTaxPilot imports from any exchange CSV and scans 6+ blockchains. Captain Tax (our AI copilot) flags issues like missing cost basis, orphan sells, and potential duplicates before you calculate. The goal is zero surprises when you file.