What is the Bitcoin halving?

What exactly gets cut in half?

New bitcoin does not come from a company or a central bank. It enters circulation only one way: as a reward to whoever adds the next block to the blockchain. The original Bitcoin whitepaper describes this as the first transaction in each block creating new coins for the block’s creator, with any transaction fees in the block added on top.

That new-coin part of the reward is called the block subsidy. The halving cuts only the subsidy. Transaction fees are paid by users and are not halved.

The rule lives in Bitcoin Core, the reference software, in a short function called GetBlockSubsidy(). It starts the subsidy at 50 BTC and halves it once for every 210,000 blocks that have passed. The comment in the code reads: “Subsidy is cut in half every 210,000 blocks which will occur approximately every 4 years.”

Why does it happen roughly every four years?

Because the halving is tied to block count, not to dates. Bitcoin’s network settings aim for one new block every 10 minutes, and the puzzle difficulty is recalculated every 2,016 blocks (two weeks at that pace) to keep blocks close to that target. The US National Institute of Standards and Technology (NIST) describes the same mechanism.

The arithmetic: 210,000 blocks × 10 minutes = 2,100,000 minutes, which is about 1,458 days, or roughly four years. Real block times vary, so the actual gap between halvings can be a little shorter or longer. That is why the code says “approximately”. It is also why we list halvings by block height rather than by calendar date.

What is the full Bitcoin reward schedule?

The table below is worked out directly from the constants in Bitcoin Core (50 BTC starting subsidy, 210,000 blocks per era), using the same whole-number arithmetic the software uses. Each row is one “era” between halvings.

How to read it: era 1 alone issued 210,000 × 50 = 10,500,000 BTC, half of everything the schedule will ever create. After four eras, the schedule had issued 19,687,500 BTC, about 93.75% of its final total. Each later era adds half as much as the one before.

The “running total” is the most the rules allow by the end of each era. It is not a live count of coins in circulation. That figure changes with every block, and we have not quoted it here.

When does the last halving happen?

Because the software counts in satoshi (1 BTC = 100,000,000 satoshi) and rounds down at each halving, the subsidy eventually becomes zero. By our calculation the last era with any subsidy is era 33 (blocks 6,720,000 to 6,929,999), where the reward is 1 satoshi per block. From block 6,930,000 the subsidy is zero. The code also forces it to zero after 64 halvings as a safety rule.

Summing every era gives 2,099,999,997,690,000 satoshi, or 20,999,999.9769 BTC — just under 21 million. If every block took exactly 10 minutes, 6,930,000 blocks would take about 132 years, but real block times differ, so treat that as arithmetic, not a forecast. Our guide What is Bitcoin? explains where the 21 million figure does and does not come from.

What happens to miners when the reward drops?

Miners are the computers that compete to publish blocks using proof of work. After a halving, each block they win pays half as much new bitcoin as before, while fees continue as normal.

The whitepaper anticipated this. It says that once “a predetermined number of coins” have entered circulation, the incentive can move entirely to transaction fees. NIST, for its part, lists inadequate block publishing rewards among the limitations and misconceptions of blockchain technology. Neither source predicts exactly how miners will behave after any given halving, and neither do we. Our crypto mining guide covers how mining works in more detail.

Does the halving make the Bitcoin price go up?

Nobody can promise that, and we found no regulator or primary source that says it does. The halving reduces how many new coins appear per block. It does not change demand, and it does not touch the coins people already hold — a halving never halves your balance.

You will see charts online that line up past halvings with past price moves. A pattern in a handful of past events is not a mechanism, and past performance does not predict future results. The St. Louis Federal Reserve notes that no central bank controls bitcoin’s supply, but a predictable supply is not the same thing as a predictable price.

What are the risks around halving hype?

Any event with a countdown can be used to rush people into decisions. Keep these points in view:

• Prices can still fall hard. The UK Financial Conduct Authority (FCA) gives its own example: Bitcoin peaked at £93,947 on 6 October 2025 and was £65,350 on 1 December 2025, a fall of 30.44%.
• You could lose everything you put in. The FCA says that if you invest in crypto “you should be prepared to lose all your money”. EU supervisors warn prices “can fall and rise quickly over short periods of time”.
• Countdown scams. Promises of “guaranteed” high returns, unsolicited pitches and pressure to act fast are red flags listed by the US Commodity Futures Trading Commission (CFTC) and Securities and Exchange Commission (SEC). Halving countdowns are an easy hook for them. Check our crypto scam red flags before acting on any of them.
• Little protection. The FCA says it is highly unlikely you would be covered by the UK’s Financial Services Compensation Scheme for crypto losses.

Blockhorizon is an education site. Nothing here is a recommendation to buy, sell or hold Bitcoin.