EducationApril 21, 20269 min read

Every Bitcoin Halving, Explained

A primary-source walkthrough of all four Bitcoin halvings — exact blocks, dates, rewards, and market context — plus what halvings honestly do and don't predict.

Last verified: April 21, 2026. All facts below are cited to primary sources or to the site's own historical price database.

What a Halving Is

Every 210,000 blocks — roughly every four years — the reward paid to Bitcoin miners for each new block is cut in half. This event is called the halving, and it is the single mechanism that makes Bitcoin's supply finite.

The halving is not a policy decision. It is hard-coded into every Bitcoin node, specified in the Bitcoin Core source in a function named GetBlockSubsidy that computes the current reward as 50 BTC right-shifted by the halving count (Bitcoin Core, validation.cpp). When the count reaches 64, the return is forced to zero as a safety belt against undefined behavior on over-wide right-shifts; in practice the subsidy reaches zero satoshis well before that, after 33 halvings.

Four halvings have occurred. Twenty-nine more will follow before the subsidy is permanently zero. This article covers each completed halving — exact block, date, reward before and after, and the market context — and then explains what halvings do and do not predict.

The Math: 21,000,000 Coins by Design

The supply schedule is specified in two places in the Bitcoin Core source. In chainparams.cpp, the line consensus.nSubsidyHalvingInterval = 210000 sets the interval for the main network (Bitcoin Core, chainparams.cpp). In validation.cpp, GetBlockSubsidy starts at a subsidy of 50 BTC per block and halves by integer right-shift on each 210,000-block milestone.

The schedule produces a predictable issuance curve. The first five eras (four already completed, one in progress):

•Era 1 — Block 0 to 209,999 — 50 BTC per block
•Era 2 — Block 210,000 to 419,999 — 25 BTC per block
•Era 3 — Block 420,000 to 629,999 — 12.5 BTC per block
•Era 4 — Block 630,000 to 839,999 — 6.25 BTC per block
•Era 5 — Block 840,000 to 1,049,999 — 3.125 BTC per block *(current)*

Because of how integer arithmetic rounds down, the asymptotic total supply is not precisely 21,000,000 BTC — the Bitcoin Wiki records it as 20,999,999.9769 BTC, and the last fractional Bitcoin is projected to be mined around May 2140 (Bitcoin Wiki, Controlled supply). For practical purposes, the 21 million cap is the canonical figure.

At roughly 10 minutes per block, 210,000 blocks is about four years of elapsed time. The actual interval drifts — sometimes the network mines slightly faster, sometimes slower — which is why halving dates are predicted in block numbers first and calendar dates second. See the Difficulty Adjustment glossary entry for how the network keeps the 10-minute average stable.

The First Halving — November 28, 2012

Block 210,000 was mined at 15:24:38 UTC on November 28, 2012 (mempool.space, block 210000). The block was found on Slush Pool (Bitcoin Wiki, Halving day 2012). The subsidy fell from 50 BTC to 25 BTC, and Bitcoin entered Halving Era 2.

The price that evening closed at $12.22 on Bitstamp-era exchanges. It had been drifting sideways for more than a year, still 59 percent below its June 2011 peak of $32. The market reception was subdued — the halving had been anticipated for months, and the community vocabulary that would later wrap the term "supply shock" around these events had not yet formed.

On-chain, the network looked microscopic by later standards. Daily hash rate was roughly 29 gigahash per second, active addresses were near 34,000, and the entire transaction count of a typical day was well under 50,000. A single modern ASIC today would outpace the entire network that secured the first halving.

Twelve months later, the price had climbed past $1,000 for the first time, peaking on November 29, 2013 near $1,132. Whether the halving caused that run or merely preceded it is a question this article returns to below.

See the full daily data at /historical-price/2012-11-28.

The Second Halving — July 9, 2016

Block 420,000 was mined at 16:46:13 UTC on July 9, 2016 by F2Pool (mempool.space, block 420000). The subsidy fell from 25 BTC to 12.5 BTC. Network transition: Era 3.

The price closed at $647.78, still 43 percent below the 2013 high near $1,132. The network that mined the second halving was a meaningfully different operation than the one that mined the first: ASIC miners had displaced GPUs, daily hash rate had crossed 1.58 million gigahash (1.58 petahash) — roughly fifty-five thousand times the level at the first halving — and mining had consolidated into a handful of large pools. Active on-chain addresses had grown to around 357,000 per day, an order of magnitude above the first-halving era.

Seventeen months later, Bitcoin peaked at $18,953 on December 17, 2017 — a roughly 29-fold move from the halving close.

See /historical-price/2016-07-09 for daily detail.

The Third Halving — May 11, 2020

Block 630,000 was mined at 19:23:43 UTC on May 11, 2020 by AntPool (mempool.space, block 630000). The subsidy fell from 12.5 BTC to 6.25 BTC. Network transition: Era 4.

The third halving occurred under unusual conditions. The price that day closed at $8,572, still 55 percent below the 2017 peak and only two months removed from the March 12, 2020 "Black Thursday" crash during the COVID-19 panic. The site's cycle-stage classifier labels this moment as accumulation, not bull.

The underlying network, however, had grown continuously through the bear market. Daily hash rate had crossed 125 exahashes per second, roughly eighty times the level at the second halving and several billion times the level at the first. Active addresses per day had reached about 645,000. Industrial-scale mining had become a capital-expenditure business with margins directly priced off the halving schedule.

Eighteen months later, the price peaked at $64,921 on November 10, 2021 — a roughly 7.6-fold move from the halving close.

See /historical-price/2020-05-11 for the full session data.

The Fourth Halving — April 20, 2024

Block 840,000 was mined at 00:09:27 UTC on April 20, 2024 by ViaBTC (mempool.space, block 840000). The subsidy fell from 6.25 BTC to 3.125 BTC. Network transition: Era 5.

Two things distinguish the fourth halving from the first three. First, the same block also carried the first etching of the Runes protocol — a UTXO-based fungible-token standard timed to activate at the halving height — which drove transaction fees on this single block to approximately 37.6 BTC, the largest fee take on any block up to that date. Second, the halving arrived while the price was close to an all-time high rather than in accumulation: $64,990 on Bitstamp the day of, only 11 percent below the pre-halving peak of $73,121 set six weeks earlier.

Roughly eighteen months later, the price set a new all-time high of $124,728 on October 6, 2025 — the current peak as of this article's verification date.

See /historical-price/2024-04-20 for the full day.

Future Halvings

At an average of about four years per cycle, the fifth halving is expected around March or April 2028, with block 1,050,000 cutting the subsidy to 1.5625 BTC. The exact date will be set by the network's block production rate, which fluctuates inside the two-week difficulty adjustment window.

Thirty-three total halvings will occur before the block subsidy reaches zero — at which point miner revenue comes entirely from transaction fees. The Bitcoin Wiki projects the last fractional Bitcoin to be mined around May 2140, assuming the network's 10-minute target holds on average (Bitcoin Wiki, Controlled supply).

By 2032, approximately 99 percent of all Bitcoin that will ever exist will have already been mined.

See the Halving Events and Key Milestones & Halvings lessons for the broader timeline.

What Halvings Do and Don't Predict

Four is not enough data points to make statistical claims, and no responsible Bitcoin writer should pretend otherwise. What can honestly be said:

Halvings reliably cut new supply in half. That is what they are designed to do, and all four have executed exactly on schedule. Daily new Bitcoin production dropped from roughly 7,200 to 3,600 to 1,800 to 900 to 450 coins per day across the four transitions.

Each cycle so far has peaked 12–18 months after its halving. That pattern has held four times. It may hold again; it may not. Correlation across four events is not a law of nature, and the structural context of each cycle (Mt. Gox dominance in 2012, retail mania in 2017, pandemic monetary expansion in 2020–2021, institutional ETF flows in 2024–2025) has differed substantially every time.

Halvings change mining economics, not price directly. The subsidy cut instantly reduces miner revenue per block by 50 percent, forcing inefficient operations offline until either price or fees compensate. That is the direct, reliable effect. Whether markets re-price over subsequent months is a separate question that depends on demand conditions unrelated to the halving itself.

Writers who claim halvings "cause" bull markets are conflating correlation and causation. Writers who dismiss halvings as marketing ignore that the supply schedule is enforced by every node running the software, not by a marketing team.

Sources

Tier A — primary sources (Bitcoin Core code and on-chain data):

Tier B — community wiki (secondary corroboration):

Price data: The site's own price-history database (bitcoin_history.db), sourced from Bitstamp, CoinGecko, and early-history CSV archives. Not externally cited.

Educational content only — not financial advice. Bitcoin is volatile; past performance does not predict future returns.

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