Bitcoin supply

Every Bitcoin block mints a fixed subsidy that halves every 210,000 blocks (~4 years). The geometric series of subsidies converges to 20,999,999.9769 BTC, not a round 21 M; each block's subsidy is an integer-sat bit-shift of 50 BTC, and the floor-truncation across all 64 halvings shaves the asymptote by 0.0231 BTC. This page shows where we are right now versus that ceiling.

Circulating supply over time

Snapshotted every 6 hours via gettxoutsetinfo on our own Bitcoin Core 28 node. This is the actually-minted supply, not the deterministic schedule. They diverge by tiny amounts because the schedule assumes exact 10-minute blocks; the chain runs slightly faster or slower per epoch.

Why "20,999,999.9769" and not 21,000,000

Bitcoin Core implements the subsidy as INITIAL_SUBSIDY_SATS >> halvings_done: a right-bit-shift on a 64-bit integer. Each halving floor-truncates fractional satoshis that the math would otherwise carry into the next epoch. Sum the full geometric series of floor'd subsidies across all 64 halvings (after which the integer subsidy is zero), and you get 20,999,999.9769 BTC. The "21 million" figure is the rounded asymptotic limit, not the actual ceiling.

For the deterministic supply curve (schedule, not observed) plus the full halving timetable through 2140, see /reports/halvings.