What was the block height of the first Bitcoin halving?

The first Bitcoin halving occurred at block height 210,000.

Bitcoin began with a 50 BTC mining reward for each block. Its protocol reduces that subsidy by half every 210,000 blocks, so the reward changed from 50 BTC to 25 BTC at the first halving on November 28, 2012. The event was reached after roughly four years of network operation, although Bitcoin does not schedule halvings by calendar date.

A common mix-up is to choose 420,000 or 630,000. Those are the block heights of the second and third halvings, in 2016 and 2020. The fourth halving took place at block 840,000 in 2024. “Block height” counts the number of blocks since the genesis block, which is height zero, so the first halving is identified by 210,000 rather than by its approximate date alone.

The reduction applies to the block subsidy, not necessarily every fee a miner earns from transactions.