How to find the cost basis of crypto transferred from another exchange

Basis is a fact about how you acquired the coins, not about where they sit now. A transfer carries units, not purchase history. Coinbase's help pages say plainly that for coins deposited from an external wallet or another exchange it does not have the original purchase records.

The IRS digital-asset FAQs say that moving assets between wallets or accounts that belong to you is not a taxable event in itself, except for any units used to pay the transaction fee. So the evidence that matters sits on the sending side, and your job is to connect the two ends of the transfer with proof.

Work backwards from the account where the coins now are. Write down what the receiving record shows before you look anywhere else.

A transfer has two ends, and they rarely look identical. The sending side usually shows a larger amount, because the network fee comes out of the transfer, and an earlier time, because the network needs minutes or hours to confirm.

Once the origin is clear, pull the full history from that exchange rather than a single statement. Look for the complete transaction or trade history export and any tax or account statement for the years involved.

For each lot that ended up in the deposit, capture the date acquired, the units, the price paid in US dollars including fees, and how you acquired it. A purchase, a conversion from another coin and a reward are different kinds of acquisition, so label each one. Bank or card statements can back up fiat purchases when the exchange record is thin.

A single deposit can contain several purchases. One row per lot keeps the evidence usable.

Keep the network fee as its own item: asset, amount and where it was paid. The IRS FAQs say units used to pay for transaction services are a disposition of those units, so your preparer may need the figure.

IRS guidance for 2025 onward, including FAQs 82 to 85, discusses identifying which units were sold when you hold the same asset across wallets and accounts. That makes it useful to record which wallet or account each lot sat in before the move. Which method applies to you is a question for your tax professional.

Cross-chain bridges and swaps in the middle of a trail appear as separate transactions on each network, so a single hash will not connect the ends. Treat each hop as its own link and document it.

The IRS says taxpayers must keep records sufficient to establish the positions on their returns, which can include records of receipts, sales, exchanges and transfers. A lot table makes those records readable. Leave an open item instead of filling a gap with a guess, a zero, or a market price nobody can trace.

If your coins came from one exchange with a complete export, the steps above, Coinbase's transaction editor for adding lots and your tax software are usually enough. Many tax tools try to match transfers between connected accounts, so check whether yours flags the ones it could not match. The sending exchange's support can help with exports.

It gets harder when there are several origins, wallets in a chain, bridges, exports with missing rows, or an account you can no longer reach. The Coinbase missing cost basis checklist, unmatched crypto transfers and Binance CSV reconciliation cover those pieces.

BasisRestore reviews qualified cases and prepares an Evidence Pack with a source map, reconciled ledger, decision log and open-items list; the synthetic sample shows the format. The free no-upload check tells you whether your case fits. BasisRestore does not give tax advice or file returns, and never asks for seed phrases, private keys, exchange passwords or withdrawal-enabled API keys.