What is a Bitcoin halving, and why miners care
The Bitcoin halving cuts the block subsidy in half every 210,000 blocks, roughly every four years. The subsidy has been 3.125 BTC since block 840,000 on 20 April 2024, and the next halving, at block 1,050,000, is estimated for around April 2028. This explainer covers the schedule, what changes for miners and what past halvings show, with no price predictions.
Category: Mining and the Network · Published 2026-10-28
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Bitcoin's issuance is on a fixed clock
New bitcoin is created only one way: as part of the reward a miner earns for adding a block. That new-coin part, the block subsidy, isn't fixed forever. Every 210,000 blocks, roughly every four years, it is cut in half.1 This event is the halving. It happens at a block height, not on a calendar date, which is why its date can only be estimated in advance.
Every full node enforces the rule and rejects any block whose miner pays itself more than the subsidy plus fees.1 Changing the schedule would mean persuading node operators to run different rules (see soft forks and hard forks).
The halving schedule so far
- 3 January 2009 (block 0): 50 BTC per block
- 28 November 2012 (block 210,000): 25 BTC
- 9 July 2016 (block 420,000): 12.5 BTC
- 11 May 2020 (block 630,000): 6.25 BTC
- 20 April 2024 (block 840,000): 3.125 BTC, the subsidy ever since
- Next: block 1,050,000: 1.5625 BTC, estimated for around April 2028
Each date is the day that block was mined.2 On 27 October 2026 the chain stood at block 973,449, about 76,550 blocks short of the next halving; the difficulty page shows the current block.4 At ten minutes a block that is roughly 532 days, putting it around April 2028 (worked out by us). That date is an estimate: blocks rarely arrive exactly ten minutes apart, so it can move by weeks.
Total issuance approaches a limit just under 21 million coins, 20,999,999.9769 BTC, and the last new coins are projected to be mined around the year 2140.2 After that, as the whitepaper anticipated, miners would be paid by transaction fees alone; whether fees will be enough is still debated.6 By block 973,449 the schedule had released about 20.1 million, roughly 95.7% of that total (worked out by us). More in what happens as the block subsidy approaches zero.
Why miners feel it overnight
At the halving block, the subsidy in every block is cut in half at once, while a machine's electricity bill and hardware costs don't change. Fees are not halved: the block reward is the subsidy plus the fees of the transactions in the block, so how far a miner's revenue drops depends on how large fees are at the time.3 In October 2026 fees were small: block 973,262, mined on 26 October, paid 3.1542 BTC in total, so only about 0.029 BTC, under 1%, was fees (worked out by us).5
Machines that were only just covering their power costs can tip into a loss overnight and be switched off. If enough hashrate leaves, blocks come more slowly until the next difficulty adjustment, at most 2,016 blocks away, lowers the difficulty so blocks return to about ten minutes apart.3 After each of the four halvings so far, difficulty fell at least once within the next two adjustments and then rose again. After the May 2020 halving it fell 6.0% on 20 May and 9.3% on 4 June, then rose 14.9% on 16 June; after the April 2024 halving it fell 5.6% on 9 May and rose two weeks later.4 How much hashrate leaves depends on prices and power costs at the time, so that history is a guide, not a rule.
Halvings and price
Some people link past halvings to later price rises, on the logic that new supply shrinks while demand may not. This article makes no price prediction. Four halvings is a very small sample, plenty of other events moved the price in the same years, and the timing of each halving is known years in advance. Treat the halving as a supply fact, not a trading signal.
What it means for solo miners
For a solo miner the math is simple: you are playing a lottery for the whole block reward, so a halving makes the prize smaller in bitcoin. A block found in October 2026 pays the 3.125 BTC subsidy plus fees; after block 1,050,000 it will pay 1.5625 BTC plus fees.2 Your odds do not change at the halving itself. They depend on your hashrate against the network's difficulty: the average time to find a block is the difficulty times 2³² divided by your hashrate.7 That is an average, not a countdown, nothing about it is guaranteed, and it is not income. The odds calculator runs the numbers at the current difficulty.
FAQ
How often does the Bitcoin halving happen?
Every 210,000 blocks, which at about ten minutes a block is roughly every four years. The last one was at block 840,000 on 20 April 2024. The next, at block 1,050,000, is estimated for around April 2028, a date that moves with how quickly blocks actually arrive.
Why does the halving exist?
It is how Bitcoin's issuance schedule is written. The subsidy started at 50 BTC per block and halves every 210,000 blocks, so total issuance approaches a limit just under 21 million coins. Every full node enforces the schedule, so no miner can issue more than it allows.
Does the halving make mining unprofitable?
It halves the subsidy part of every block's revenue at a single block while costs stay the same, so machines that were only just covering their electricity can tip into a loss. Whether a machine stays profitable depends on bitcoin's price, fees, difficulty and its power cost. The difficulty adjustment restores block times, not anyone's profit.
What happens to the block reward after all halvings?
The subsidy keeps halving until it reaches zero, with the last new coins projected around 2140. After that, miners would be paid by transaction fees alone, and whether that will be enough is an open question.
Key takeaways
- The block subsidy halves every 210,000 blocks, roughly every four years, at a block height rather than on a calendar date.
- It has been 3.125 BTC since block 840,000 on 20 April 2024 and drops to 1.5625 BTC at block 1,050,000, estimated for around April 2028.
- Fees are not halved, but they were a small part of the block reward in October 2026, so a halving still cuts miners' revenue sharply.
- After each of the four halvings so far, difficulty fell at least once within the next two adjustments and then rose again.
- A halving shrinks a solo miner's prize but not the odds, and an expected time to a block is an average, not a countdown.
Sources
- Bitcoin Core source, validation.cpp: GetBlockSubsidy starts at 50 BTC and halves it once every 210,000 blocks ('approximately every 4 years'), and blocks whose coinbase pays more than subsidy plus fees are rejected ('bad-cb-amount') — Bitcoin Core project (GitHub)
- Controlled supply: genesis block on 2009-01-03; halvings at blocks 210,000 (2012-11-28), 420,000 (2016-07-09), 630,000 (2020-05-11) and 840,000 (2024-04-20); total supply slightly under 21 million (20,999,999.9769 BTC); last new coins projected around 2140 — Bitcoin Wiki
- Bitcoin Developer Guide, Block Chain: the block reward is the block subsidy plus transaction fees, and difficulty is recalculated every 2,016 blocks so that they take two weeks (about ten minutes a block) — Bitcoin Project (developer.bitcoin.org)
- Bitcoin mining difficulty: 140.58 T at block 973,449, read from SoloLuck's own node on 27 Oct 2026 at 20:29 UTC, with every difficulty adjustment since 2009 as open data (epochs.csv), including the adjustments after each halving — SoloLuck
- Solo Block Record entry for block 973,262, mined on 26 Oct 2026: block reward 3.1542 BTC, read from the chain — SoloLuck
- Bitcoin: A Peer-to-Peer Electronic Cash System (the whitepaper), section 6: transaction fees add to the block incentive, which can transition entirely to fees once a predetermined number of coins is in circulation — bitcoin.org
- Difficulty: the average time for a miner to find a block is difficulty x 2^32 / hashrate — Bitcoin Wiki
Some specific claims in this article are scheduled for further source review; citations may be expanded (see our editorial policy).