Change Address

On chains that use unspent outputs, a transaction spends whole outputs rather than exact amounts, so whatever exceeds the amount being sent is returned to an address the sending wallet controls. That destination is the change address, and modern wallets generate a fresh one for each transaction rather than sending change back to the original address. Two practical consequences follow. A block explorer will show what looks like a second, unexplained payment to an unfamiliar address, and it is usually your own change rather than a leak. And because change addresses are derived from the same recovery phrase, restoring a wallet recovers them too — they are not a separate thing to back up. The risk sits in manual key handling rather than in normal use: tools that sweep a raw private key can be configured to send the remainder somewhere the user does not control. Account-based chains have no change at all, because a balance is debited directly.