Definition
Confirmation time is the interval between broadcasting a Bitcoin transaction and a miner including it in a block, giving it its first confirmation. Bitcoin targets one block roughly every ten minutes, so a well-fee'd transaction broadcast just after a block is found may confirm within minutes, while one broadcast just before a block tends to wait for the next round.
What drives confirmation time
The dominant factor is the fee rate, expressed in satoshis per virtual byte, relative to what other transactions in the mempool are offering. Miners assemble blocks to maximize fee revenue, so they select the highest-paying transactions first. When the mempool is congested, a low-fee transaction can wait hours or days; when it is empty, even a minimal fee may confirm in the next block. Block discovery is also a random Poisson process, so individual intervals vary widely around the ten-minute average.
Estimating and improving it
Fee-estimation tools and mempool explorers predict how many blocks a given fee rate will take to confirm. A transaction that is stuck because it underpaid can sometimes be sped up using fee-bumping techniques rather than waiting indefinitely.
For the underlying mechanics, see unconfirmed transaction and transaction accelerator.
In Simple Terms
Confirmation time is the interval between broadcasting a Bitcoin transaction and a miner including it in a block, giving it its first confirmation. Bitcoin targets…