Coinbase Maturity

Coinbase maturity is the Bitcoin consensus rule that newly mined coins cannot be spent immediately. The output of a coinbase transaction, which pays a miner the block subsidy plus collected fees, must wait 100 additional blocks before it becomes spendable. Because the originating block counts as the first confirmation, the reward is effectively unlocked at 101 confirmations.

Why the delay exists

The maturity rule protects the network and downstream spenders against chain reorganizations. If a competing chain overtakes the one a block was mined on, that block, and the coins it created, can vanish. By forcing a roughly 100-block waiting period, around 16 to 17 hours at the 10-minute target, the protocol makes it extremely unlikely that a reward will be reorganized out of existence after it has been spent. Without this rule, transactions built on freshly minted coins could be undone, causing losses for whoever received them.

What miners see

In mining software and pool dashboards, freshly earned rewards appear as an immature or pending balance until the maturity threshold is reached, after which they move to a confirmed, spendable balance. This is normal and is not a sign of a stuck payout.

The rule applies specifically to the special coinbase transaction at the top of every block. Learn more about the reward itself in Block Subsidy, and about the extra search space that lives inside the coinbase in Extranonce.