Term
Block confirmation
A confirmation is the inclusion of a transaction in a block plus each subsequent block built on top of it — one confirmation means one block deep, six confirmations means five more blocks were added after, which makes reversal exponentially harder.
A confirmation is how blockchains measure the finality of a transaction. When a transaction is first included in a block, it has one confirmation. Each new block added on top of that block adds another confirmation. Reversing the transaction (a "reorg") requires re-mining every block since — the probability of a successful attack drops exponentially with each confirmation.
Different chains and different receiving services require different confirmation counts. Bitcoin swaps typically wait for 1-3 confirmations (10-30 minutes) for retail amounts; large amounts sometimes wait for 6. Ethereum swaps often require 12-30 block confirmations (a few minutes). Fast chains like Solana or TRON require more because their blocks are cheaper to attack individually — but overall the total wait can still be shorter.
When a swap is stuck at "Confirming," you can check the required threshold on the block explorer and see how many confirmations your deposit currently has.
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