The genesis
block, mined January 3, 2009, is height 0. Every block since increments the counter by exactly one, so the height doubles as both a position ("which block is this?") and an age ("how long has this chain existed?"). As of late July 2026 the height is roughly 959,700 —
closing in on one million, a milestone due around spring 2027.
Bitcoin schedules everything by height because block time is the only clock all participants can agree on. Wall-clock time can be spoofed; block count can't. That's why the
halving arrives every 210,000 blocks (not "every four years" — that's just the ten-minute average doing the math), why the
difficulty adjustment fires every 2,016 blocks, and why the last satoshi will be mined near block 6,930,000, sometime around 2140. Dates are estimates; heights are commitments.