Skip to main content

Halving & cycle

Bitcoin's block subsidy halves every 210,000 blocks. The page counts the blocks left to the next halving, shows where the chain sits in the current epoch, and lists what happened at each halving so far.

Exact figures and estimated ones​

The page mixes two kinds of number, and it marks which is which.

Exact — arithmetic on the current block height, which the chain itself publishes:

  • the current height, the next halving's block, and the blocks between them
  • the current block reward and the reward after the halving, both derived from the height rather than stored, so a reward can never disagree with the epoch printed beside it
  • epoch progress: blocks mined into this epoch, out of 210,000

Estimated — anything expressed as a date or a number of days. These assume the ten-minute block target, which the network holds only on average, so they drift as hash rate changes. Every one of them is marked "est." on the page:

  • the estimated halving date and the days remaining
  • the estimated length of the current cycle, in days

The block count is the honest figure and the date is the convenient one. That is why the countdown is measured in blocks first.

Epoch, and cycle​

One progress figure, measured in blocks. The "cycle" between two halvings is the epoch, so a calendar percentage of it would track the block percentage to within about a point — two progress readings a point apart, under two labels, would read as the page disagreeing with itself.

The cycle instead reports what the block count cannot say: how many days have passed since the last halving, and roughly how many the cycle will run in total. Where we hold no record of the halving that started an epoch, those two counts read "—" rather than being estimated from something else.

Previous halvings​

Each row carries the halving's date and block, the new reward, the USD price on the day, and the highest price reached before the next halving. Prices are daily closes rounded to the dollar.

A cycle that has not ended yet has no peak: it is a running maximum, not a recorded fact. That row reads "Cycle in progress" rather than quoting a figure that would need rewriting after every new high. The peak gain column is blank for the same reason.

Freshness​

The chain tip is re-read every ten minutes. If that stops, the page keeps showing the last height we read, says when it was read, and carries on: a height half an hour old is three blocks out of six figures, and a dated reading is a better answer than a blank page. Nothing on the page is a forecast of price, and nothing on it is a recommendation.