What are inputs and outputs in a Bitcoin payment?
Ordinary payments spend previous outputs as inputs and create new outputs. Coinbase transactions, which create miner rewards, are the exception.
In an ordinary payment, each input points to an earlier output and carries proof that the sender may spend it. Each output gives an amount and spending conditions, often through an address. The coinbase transactionCoinbase transactionThe first payment in every block, created by its miner. It has no inputs and pays out the block reward. in a block does not spend a previous output.
For an ordinary payment, any difference between the input total and the output total is the fee, which the miner can claim.
References
- Bitcoin Developer Guide, “Block Chain”.