Transactions are comprised of a list of inputs, individual payments that were previously received by a wallet, and outputs, a list of amounts and addresses to which the bitcoins will be transferred.
Only the full amount of an input can be spent. If the exact amount of the transaction can’t be constructed from available inputs, an additional output, called change, is added, which sends the remainder back to a new address in the user’s wallet. Change addresses are not shown to the user.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fwe.lovebitco.in%2Fimg%2Ftransaction.png&t=665&c=8JyTk2L_MaqW1Q)
Source: see my signature