Bitcoin Halving Explained: What Changes and What History Shows
Learn what the Bitcoin halving is, how often it happens, what changes, and what history shows. A clear guide for beginners and intermediate readers.
In this article9 sections
Key points
- The Bitcoin halving cuts the reward miners receive for adding a new block to the blockchain in half every 210,000 blocks, roughly every four years.
- It reduces the rate at which new bitcoins are created, capping the total supply at 21 million coins.
- Historically, halvings have been followed by increased price volatility, but past performance does not guarantee future results.
Every four years or so, Bitcoin goes through a scheduled event called the halving. The network is at block 975,725 now, so the next halving, at block 1,050,000, is 74,275 blocks away: around April 2028 if blocks keep arriving every 10 minutes.
What is the Bitcoin halving?
The Bitcoin halving is a pre-programmed reduction in the reward that miners receive for adding a new block of transactions to the Bitcoin blockchain. When Bitcoin launched in 2009, the reward was 50 bitcoins per block. Every 210,000 blocks, that reward is cut in half. This continues until all 21 million bitcoins have been issued, after which miners will rely solely on transaction fees.
The halving is not a sudden event that changes how Bitcoin works. It is written into Bitcoin’s original code and is completely predictable. Anyone can calculate when the next halving will occur based on the current block height.
How often does the halving happen?
The halving occurs every 210,000 blocks. On average, a new block is mined every 10 minutes, so 210,000 blocks take about four years. The exact timing can vary slightly because block times are not always exactly 10 minutes, but the block count is fixed.
Here is a table of past and future halvings, with block heights and approximate dates. Note that future dates are estimates based on the average block time.
| Halving | Block height | Reward after halving | Approximate date |
|---|---|---|---|
| 1st | 210,000 | 25 BTC | 28 November 2012 |
| 2nd | 420,000 | 12.5 BTC | 9 July 2016 |
| 3rd | 630,000 | 6.25 BTC | 11 May 2020 |
| 4th | 840,000 | 3.125 BTC | 20 April 2024 |
| 5th | 1,050,000 | 1.5625 BTC | Estimated 2028 |
The current block reward is 3.125 BTC. The next halving is expected to occur when the block height reaches 1,050,000, which is estimated to happen in 2028.
What each halving did to new supply
About 144 blocks are mined a day, so the block reward sets how many new bitcoins appear each day.
| Period | Reward per block | New BTC per day (approx.) |
|---|---|---|
| 2009 to November 2012 | 50 BTC | 7,200 |
| November 2012 to July 2016 | 25 BTC | 3,600 |
| July 2016 to May 2020 | 12.5 BTC | 1,800 |
| May 2020 to April 2024 | 6.25 BTC | 900 |
| April 2024 to the next halving | 3.125 BTC | 450 |
| After block 1,050,000 | 1.5625 BTC | 225 |
At today’s rate, new issuance adds about 0.82% a year to the supply, and 95.77% of all 21 million bitcoins have already been issued. The reward rule is in Bitcoin Core’s GetBlockSubsidy function.
What changes at the halving?
Three main things change:
- Miner revenue from block rewards is cut in half. Miners receive fewer new bitcoins for the same amount of work. This directly reduces their income unless the price of Bitcoin rises or transaction fees increase.
- The rate of new Bitcoin issuance slows. Fewer new bitcoins enter circulation each day. This reduces the inflation rate of Bitcoin’s supply.
- The stock-to-flow ratio increases. This is a measure of how much existing supply compares to new production. It is often used to describe scarcity, but it is not a price predictor.
What does not change: the 21 million cap, the block time target of 10 minutes, and the rules of the network. The halving is a scheduled adjustment, not a software upgrade or a governance decision.
Why does the halving matter?
The halving matters because it controls Bitcoin’s inflation schedule. Unlike central banks, which can change money supply at will, Bitcoin’s supply growth is fixed and decreasing. The supply still grows, only more slowly after each halving, until issuance ends around the year 2140 at just under 21 million coins. The halving is a key part of that design.
For miners, the halving is a business event. They must plan for lower revenue. Some may shut down older, less efficient machines if the price does not compensate. This can temporarily reduce the network’s hash rate, but the network automatically adjusts difficulty to keep block times near 10 minutes (see how Bitcoin mining works).
What history shows
Historically, halvings have been followed by significant price volatility. In the months after the 2012, 2016, and 2020 halvings, Bitcoin’s price increased substantially. However, the 2024 halving did not produce an immediate price surge; instead, the price remained range-bound for several months. This shows that the halving is not a guaranteed price catalyst.
It is important to remember that correlation is not causation. Many factors influence Bitcoin’s price, including macroeconomic conditions, regulation, and market sentiment. The halving reduces new supply, but demand is equally important. Past performance is not a reliable indicator of future results.
Common mistakes and risks
- Expecting a guaranteed price increase. The halving does not automatically cause the price to rise. Do not invest based on the assumption that it will.
- Confusing the halving with a fork. A halving is not a change to Bitcoin’s rules; it is a scheduled reduction in the block reward. A fork would create a new cryptocurrency.
- Ignoring mining economics. If you are a miner, the halving cuts your revenue. You need to plan for higher costs or upgrade to more efficient hardware.
- Believing the halving is a surprise. It is known years in advance. Any price impact is likely already partially reflected in the market.
- Overlooking transaction fees. As block rewards shrink, transaction fees will become a larger part of miner revenue. This could affect network security and user costs in the long term.
Practical steps for beginners
If you are new to Bitcoin, here is what you can do to understand the halving better:
- Check the current block height. You can find it on any block explorer, such as mempool.space. The next halving occurs at block 1,050,000.
- Learn how mining works. Our mining guide explains why the halving matters to miners.
- Consider the long term. The halving is one part of Bitcoin’s monetary policy. It is not a short-term trading signal.
Disclaimer: This article is for information only and is not investment, financial or trading advice. Cryptocurrency prices are highly volatile. Always do your own research.
