Why does my withdrawal fee not match the transaction fee I'm seeing on a block explorer website?

Question

Sent ~$7 worth of BTC from a Coinbase wallet, to a cold wallet. Coinbase charged a ~$2 "network fee".

Make sense so far, but the transaction listed on blockchain.com shows a magnitudes larger fee: ~$80

The receiving cold wallet app shows the $7 received and also displays the ~$80 fee, in its confirmed transaction history.

• Who paid that fee ?
• Why would they do that and how does it make sense on a small transaction ?
• Where did the $2 fee go and why is it not listed anywhere on the blockchain transaction ?

Answer 1

As an aside, Bitcoin transaction fees are paid in BTC, not in dollars. To understand how and why bitcoin transaction fees work, you need to consider them in this way.

From what you have written, it sounds like Coinbase batches withdrawals, which means they will pay many of their customers at once, in a single bitcoin transaction. A transaction can have 1 or more inputs, and 1 or more outputs, so if you have to pay many people, you can save costs by sending one transaction, which pays all of those people at once, rather than individual transactions witch pay them one at a time.

When Coinbase processes your withdrawal, they can charge you whatever they would like ($2 in this case). But the actual transaction fee that Coinbase paid to make that bitcoin transaction was apparently around ~$80 worth of BTC. Whether the sum of all fees they charged their customers would be equal to this amount, or more, or less, is all just a matter of Coinbase's company policy.