Bitcoin Cash and Bitcoin use the same issuance schedule. Both started from the same chain, both cut the block reward in half every 210,000 blocks, and both will halve next at block 1,050,000. Still, the two halvings do not happen on the same day. This guide explains why.
One chain until August 2017
Until block 478,558 there was only one chain. On 1 August 2017 Bitcoin Cash continued with larger blocks while Bitcoin kept the one-megabyte limit and later added SegWit. Everything before the split is common history, including the halvings at block 210,000 (November 2012) and block 420,000 (July 2016).
After the split each chain produced its own blocks. The rule stayed the same on both sides: 50 coins at the start, halved every 210,000 blocks, which adds up to just under 21 million coins.
Why the block heights drifted apart
The halving is triggered by block height. The two chains count separately, and they did not find blocks at the same speed:
- Right after the split Bitcoin Cash used an emergency difficulty rule that at times produced many blocks in a short period.
- In November 2017 Bitcoin Cash changed its difficulty algorithm, and in November 2020 it changed it again to ASERT, which adjusts with every block.
- Bitcoin adjusts its difficulty every 2,016 blocks. While hashrate grows, its blocks arrive slightly faster than every ten minutes.
The result is a gap of a few thousand blocks. The third halving shows it well: Bitcoin Cash reached block 630,000 on 8 April 2020, Bitcoin about a month later. The fourth halving at block 840,000 came on 3 April 2024 on Bitcoin Cash and a little over two weeks later on Bitcoin.
Which chain is ahead today, and by how many blocks, is shown live on the halving race page.
What is identical
| Bitcoin Cash | Bitcoin | |
|---|---|---|
| Halving interval | 210,000 blocks | 210,000 blocks |
| Reward before block 1,050,000 | 3.125 | 3.125 |
| Reward after | 1.5625 | 1.5625 |
| Target block time | 10 minutes | 10 minutes |
| Proof of work | SHA-256 | SHA-256 |
| Maximum supply | just under 21 million | just under 21 million |
What is different
- Difficulty adjustment. Bitcoin Cash adjusts every block (ASERT), Bitcoin every 2,016 blocks.
- Block size. Bitcoin Cash has a limit of at least 32 MB that can grow with usage, see block size limit.
- Fees. On Bitcoin Cash, fees are a very small part of what a miner earns per block, so the halving cuts miner income in BCH almost exactly in half. On Bitcoin, fees can be a larger share.
- Miners. The same machines can mine both chains. After a halving, miners compare what each chain pays and may move hashrate.
A third chain on the same schedule
Bitcoin SV split from Bitcoin Cash in November 2018 and kept the schedule too. It also halves at block 1,050,000, on its own day.
Reading the dates
All halving dates in the future are estimates from the measured block time of each chain. The block number is certain; the day is not. Nothing here is a price forecast or investment advice.