Block Time
The average time it takes for a new block to be added to a blockchain, determining how quickly transactions are processed.
Every blockchain adds new blocks at a roughly consistent pace. Ethereum produces a block every 12 seconds. Solana every 400 milliseconds. Bitcoin every 10 minutes. Block time directly affects how fast your transaction gets included.
Shorter block times generally mean faster transactions, but there are trade-offs. Very short block times can lead to more reorganizations (temporary disagreements about which blocks are valid). Most modern chains have found a good balance.
For USDC users, block time affects how quickly your transfer is confirmed. On Solana, your USDC arrives in under a second. On Ethereum, you'll typically wait 12-24 seconds for initial confirmation. On Bitcoin (if it supported USDC), you'd wait 10 minutes.
Related Terms
Confirmation
The number of new blocks added to the blockchain after your transaction's block, indicating how settled the transaction is.
Finality
The point at which a blockchain transaction becomes irreversible and can never be changed or rolled back.
Blockchain
A distributed, immutable digital ledger that records transactions across a network of computers.
Validator
A computer that verifies transactions and adds new blocks to a proof-of-stake blockchain.
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This definition is provided for educational purposes. USDC.org is an independent resource and is not affiliated with Circle Internet Financial.