$BTC Lost Bitcoin: Lost Keys and Erroneous Transfers

It is difficult to provide an exact figure, but it is estimated that between 17% and 23% of all mined Bitcoin is permanently lost or inaccessible. This is primarily due to lost private keys, forgotten passwords, or the death of owners without a succession plan. In total, this could represent between 2.3 and 3.7 million BTC that are locked on the blockchain.

The loss from transfers to incorrect networks is even harder to quantify. This occurs when Bitcoin is sent to an address on an incompatible blockchain network.