What Is the Bitcoin Halving? A Plain Guide, Block by Block

The Bitcoin Halving is a rule in Bitcoin’s code that cuts the reward for mining a new block in half every 210,000 blocks, roughly every four years. It began at 50 BTC per block in 2009. Since April 2024 it has been 3.125 BTC. The next cut, at block 1,050,000, lowers it to 1.5625 BTC around April 2028.

That is the whole definition. Everything below is the same sentence, unfolded slowly, for anyone who has heard the word and nodded without being sure what it meant.

What does the Bitcoin halving actually do?

Every block on the Bitcoin chain pays the miner who found it. The payment has two parts. The first is the transaction fees inside the block, paid by people sending bitcoin. The second is the block subsidy: brand new bitcoin, created out of nothing, in the very first transaction of the block.

The subsidy is the only way new bitcoin ever comes into existence. There is no other faucet. No central bank, no foundation, no reserve.

The halving cuts that subsidy, and only that subsidy, in half. Fees are untouched. So when people say “the halving cuts miner rewards”, they mean the new-coin half of the reward. The fee half floats with demand for block space.

In practice, at about 144 blocks a day, the current subsidy of 3.125 BTC means roughly 450 new bitcoin enter the world daily. After the next cut it will be about 225. That is the entire monetary policy of Bitcoin. A number, a divisor, and a clock that ticks in blocks.

Why every 210,000 blocks?

Satoshi Nakamoto described the plan in the email that announced the first release, sent on 8 January 2009. In the Bitcoin v0.1 announcement, the schedule is laid out in plain terms: a total of 21,000,000 coins, with the amount cut in half every four years. The same email lists the first four years as 10,500,000 coins, then 5,250,000, then 2,625,000.

Do the arithmetic and the 210,000 appears. Bitcoin aims for one block every ten minutes. Six an hour, 144 a day. Four years of that is about 210,240 blocks. And 210,000 blocks at 50 BTC each is exactly 10,500,000 coins, the number in the email.

Here is the part beginners usually miss. The halving is triggered by block height, not by a date. Nobody schedules it. No one presses a button. When block 1,050,000 is mined, the rule applies to that block, whatever the calendar says. Four years is a translation. The height is the law.

That is why every forecast of the next halving date shifts a little from month to month. Blocks arrive slightly faster or slower than ten minutes depending on how much mining power joins the network between difficulty adjustments. The height never moves. The date drifts around it.

How is the Bitcoin block reward calculated?

The rule fits in a few lines of C++. In GetBlockSubsidy in Bitcoin Core, the software takes the block height, divides it by 210,000, drops the remainder, and calls the result the number of halvings so far. It then starts from 50 BTC and shifts the value right by that many bits. A right shift by one is division by two. A right shift by two is division by four.

Written as a formula:

subsidy = 50 BTC ÷ 2^(floor(height ÷ 210,000))

The value is held in satoshis, the smallest unit (one bitcoin is 100,000,000 satoshis), and it is a whole number. When halving would leave a fraction of a satoshi, the fraction is simply dropped. The code also carries a guard: once the count of halvings reaches 64, the subsidy is forced to zero, because a 64-bit shift is undefined in the language.

A block that tries to pay its miner more than subsidy plus fees is invalid. Every full node checks this independently. That is what makes the halving binding: not a promise from a company, but a check run by thousands of machines that will refuse the block.

Here is the schedule so far, with the next cut.

Era	Block heights	Subsidy per block	Began
Launch	0 to 209,999	50 BTC	January 2009
After 1st halving	210,000 to 419,999	25 BTC	November 28, 2012
After 2nd halving	420,000 to 629,999	12.5 BTC	July 9, 2016
After 3rd halving	630,000 to 839,999	6.25 BTC	May 11, 2020
After 4th halving	840,000 to 1,049,999	3.125 BTC	April 20, 2024 (UTC)
After 5th halving	1,050,000 to 1,259,999	1.5625 BTC	expected around April 2028

The exact UTC times, mining pools and fees of each past cut are on the Bitcoin Halving history page.

Why does the Bitcoin halving matter?

Because it is the supply schedule, and the supply schedule is the one thing about Bitcoin that is known in advance.

Every halving cuts the rate of new issuance. At block 969,862, the chain tip on 5 October 2026 according to mempool.space, about 20.09 million bitcoin have been issued, roughly 95.7 percent of the eventual total. At 450 new coins a day against that base, annual issuance is a little over 0.8 percent. After the 2028 cut it falls to roughly 0.4 percent. The inflation rate of Bitcoin halves on a timetable, and it can be read years ahead.

The halvings are also why the supply has a ceiling. A series that starts at 50 and halves forever sums to a finite number. Add it up block by block, with the integer rounding the code applies, and the total is not quite 21 million. Bitcoin Core’s own consensus test for the subsidy limit asserts the exact figure: 2,099,999,997,690,000 satoshis, or 20,999,999.9769 BTC. The famous 21 million is a rounding of a number that falls short by a little over two hundredths of a coin.

For miners, the halving is a pay cut overnight. A machine that earned a certain amount of bitcoin per day on block 839,999 earned roughly half the subsidy on block 840,000. The metric miners watch for this is hashprice, and the hashprice reference explains how each cut drops it in a single block.

For everyone else, the halving is a reminder of what kind of money this is. Its issuance does not respond to elections, emergencies or committees. If you have ever watched the purchasing power of a salary leak through a bag with holes, that indifference is the point.

Does the halving make Bitcoin’s price go up?

Sometimes the price rose afterward. That is not the same as the halving causing it.

The record is short. According to CoinGecko’s halving price history, the price twelve months after each of the first three cuts looked like this:

Halving	Price near halving day	Price about 12 months later
November 2012	about $12	about $1,075
July 2016	about $650	about $2,560
May 2020	about $8,727	about $55,847

Three data points. Each rise smaller in percentage terms than the one before. Each one tangled with other causes: new exchanges, a wave of token sales in 2017, pandemic-era money printing and corporate buying in 2020 and 2021. The 2024 cut came after the price had already set a new all-time high in the weeks before the halving, which made the old story harder to tell.

The honest summary is this. The halving reduces the flow of new coins that miners must sell to cover costs. Whether that matters to price depends on demand, which no code controls. Anyone who tells you the halving guarantees a rally is selling something. None of this page is financial advice.

How many Bitcoin halvings are left?

Four have happened. Twenty-nine remain on the site’s count, the next at block 1,050,000 in 2028.

The subsidy keeps halving until it is so small that halving it once more leaves nothing. That happens at block 6,930,000, expected around the year 2140. After that block, new issuance is zero and miners are paid by fees alone. The detailed answer, including the arithmetic of the last few satoshis, lives on when is the last Bitcoin Halving. The calendar estimate for the next one, with the current block countdown, is on the next Bitcoin Halving page.

At today’s height there are 80,138 blocks left before block 1,050,000. At exactly ten minutes a block that lands in mid April 2028. It will not be exactly ten minutes. It never is.

What skeptics say

The skeptic has fair points, and a beginner should hear them.

First, the 21 million cap is a rule, and rules can in principle be changed. Bitcoin’s supply holds because the people running nodes refuse blocks that break it, not because mathematics forbids a different program. So far, every attempt to imagine a change has met that refusal. That is a social fact, and social facts can drift.

Second, the security budget. As the subsidy shrinks, miners depend more on fees. If fees stay low for decades, the cost of attacking the chain may fall relative to its value. This debate is real and unresolved. It will not be settled in this cycle or the next.

Third, the price story is mostly narrative. A schedule known to everyone years in advance should, in theory, already be priced in. The pattern of the first three cuts may be coincidence dressed as law.

All three are worth sitting with. None of them changes what the halving is. They only argue about what it means.

The Halfture, and why this site exists

This is a reference page, so here is the reference, stated once. Every halving so far has been an ordinary halving. Four cuts done, twenty-nine to go. Each one rehearses the last.

The last one has a name here. We call it the Halfture: the final cut at block 6,930,000, when the subsidy reaches zero and the issuance of new bitcoin ends for good. It has not happened. It will not happen in any of our lifetimes. The schedule walks toward it one block at a time, and it does not hurry.

The rest of this site reads that schedule the way older texts read the end of things. The Halfture is the Rapture, in the only sense we mean it: the moment the supply is finished and the waiting is over, for the coins at least. Every cut before it is a small-h halving, a rehearsal for an ending that comes whether anyone is watching or not.

And here is the doctrine, which is theology, not a prospectus. On this site we say you have to hold Bitcoin to be saved. It is a statement of faith about money and time, not a recommendation about your portfolio, and nothing on this page is financial advice. You can understand the halving completely and disagree with every word of that sentence. The rule in the code will not mind.

The definition is simple. A number, halved, on a clock made of blocks. Read the code. Count the blocks.

Look into it.

FAQ

What is the Bitcoin halving in simple terms?

It is an automatic cut in the number of new bitcoin created with each block. Every 210,000 blocks, about every four years, the block subsidy paid to miners is divided by two. It started at 50 BTC, is 3.125 BTC today, and drops to 1.5625 BTC at block 1,050,000.

How often does the Bitcoin halving happen?

Every 210,000 blocks. Because blocks arrive about every ten minutes, that works out to roughly four years, but the trigger is block height, not a calendar date. The past cuts landed in November 2012, July 2016, May 2020 and April 2024.

Does the halving make Bitcoin’s price go up?

Not reliably. Price rose in the year after each of the first three halvings, but by smaller percentages each time, and other causes were always present. The halving reduces new supply; demand is outside the code. This is not financial advice.

What happens when all bitcoin are mined?

After block 6,930,000, expected around 2140, the block subsidy is zero and no new bitcoin are created. Miners keep securing the network for transaction fees alone. The total supply ends at 20,999,999.9769 BTC, slightly under 21 million because of integer rounding.

How many Bitcoin halvings are left?

Twenty-nine on this site’s count, from block 1,050,000 in 2028 through block 6,930,000, the final cut around 2140. Four have already happened.