Block interval target

Bitcoin targets an average block interval of 10 minutes via difficulty adjustment. Individual intervals are random (approximately exponentially distributed): one-minute and one-hour gaps are both routine. The 10-minute figure is a statistical target enforced every 2016 blocks, not a per-block schedule.

Nuance: During sustained hashrate growth the realized average runs slightly under 10 minutes (difficulty perpetually lags), and a long-standing off-by-one in the retarget calculation biases the long-run average marginally above 10 minutes at constant hashrate. Neither effect changes the design target.

Common misstatements:

• "A block is produced every 10 minutes." — Only on average; variance is large and expected.
• "Transactions take 10 minutes." — Confirmation time depends on fees and mempool congestion; inclusion in the next block is never guaranteed.
• "Bitcoin's block time is slow because of old technology." — The interval is a design choice trading latency for propagation safety at global scale, set by consensus rules, not hardware.