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Bitcoin's history.

On 31 October 2008, Satoshi Nakamoto emailed a nine-page paper to a cryptography mailing list. Everything that followed is here, from two pizzas bought for 10,000 BTC to the halving due in 2028, each with its source and, where it happened on-chain, its block.

Price in US dollars from mempool.space, weekly from July 2010, on a log scale so each step up is ten times the one below. Each event sits on the line at the price of its day. Dates after 30 Oct 2026 are estimates from recent block times.

2009 to 2012

Miners earned 50 BTC a block until block 210,000, on 28 November 2012.

  1. 15 Aug 2010

    The value overflow incident

    A transaction in block 74,638 created about 184 billion bitcoin by exploiting a bug in how the software added up large amounts. Satoshi Nakamoto released a fix, Bitcoin 0.3.10, the same day, and the network replaced the bad block.

    Network · Until 16 AugSee block 74,638SourceBitcoin Wiki, Value overflow incident

  2. 21 Nov 2011

    Bitcoin 0.5.0 brings the Bitcoin-Qt window

    Bitcoin 0.5.0 replaced the program's window with "a completely new graphical interface that uses the Qt user interface toolkit", released as Bitcoin-Qt. Mara van der Laan had started it as a separate project in May 2011, and took over Bitcoin Core from Gavin Andresen in 2014.

    NetworkSourceBitcoin.org, Bitcoin Core version 0.5.0 released (21 November 2011)

  3. 1 Apr 2012

    Pay to script hash (P2SH) activates

    Pay to script hash (P2SH, BIP 16) took effect from block 173,805, the first block timestamped after midnight UTC on 1 April 2012. It lets anyone pay to a short address starting with 3 that stands for spending rules of any complexity, such as needing several signatures, which the recipient reveals only when spending.

    Network · 00:43 UTCSee block 173,805SourceBIP 16, Pay to Script Hash (rules apply to blocks with timestamps >= 1333238400, Apr 1 2012)

2012 to 2016

Miners earned 25 BTC a block until block 420,000, on 9 July 2016.

  1. 28 Nov 2012

    The first halving

    At block 210,000 the reward for mining a block fell from 50 to 25 bitcoin, the first halving. The software halves the reward every 210,000 blocks, roughly every four years.

    Network · 15:24 UTCSee block 210,000SourceBitcoin Core source, nSubsidyHalvingInterval = 210000

  2. 19 Feb 2013

    Bitcoin 0.8 keeps a set of unspent coins

    Bitcoin 0.8.0 was released. Built on a change by Pieter Wuille, it checked new transactions against a database of only the unspent outputs, now called the UTXO set, instead of an index of every past transaction, which made it much faster. It also moved from Berkeley DB to LevelDB, which three weeks later let it accept a block that older versions rejected, splitting the chain.

    NetworkSourceBitcoin.org, Bitcoin Core version 0.8.0 released (19 February 2013)

  3. 11 Mar 2013

    The March 2013 chain split

    A large block at height 225,430 was accepted by Bitcoin 0.8 but rejected by older versions, splitting the blockchain in two. Large mining pools switched back to version 0.7 so the network reunited on the older versions' chain.

    Network · Until 12 MarSee block 225,430SourceBitcoin.org, 11/12 March 2013 Chain Fork Information

  4. 10 Sept 2013

    BIP 39 sets out recovery words

    Marek Palatinus, Pavol Rusnák and Aaron Voisine created BIP 39, a standard for writing a wallet's backup as a list of 12 to 24 words, which "could be written on paper or spoken over the telephone".

    NetworkSourceBIP 39, Mnemonic code for generating deterministic keys (Assigned: 2013-09-10)

  5. 4 Jul 2015

    The July 2015 chain split

    Just after the BIP 66 upgrade took effect, a small miner produced an invalid block at height 363,731, and large pools that were building on new blocks without checking them first ("SPV mining") added five more blocks on top. The valid chain overtook the six invalid blocks about an hour and a half later, and lightweight wallets were advised to wait for extra confirmations.

    NetworkSee block 363,731SourceBitcoin.org, Some miners generating invalid blocks (alert of 4 July 2015, all times UTC)

  6. 15 Aug 2015

    Bitcoin XT is released

    Mike Hearn and Gavin Andresen released Bitcoin XT, a version of Bitcoin's software that would raise the block size limit to 8 MB under BIP 101 once three quarters of recent blocks supported it. It never reached that level of support.

    NetworkSourceMike Hearn, "Why is Bitcoin forking?" (15 Aug 2015, archived)

  7. 7 Dec 2015

    SegWit becomes the plan for more capacity

    As the Scaling Bitcoin workshop in Hong Kong ended, Gregory Maxwell set out his plan for raising Bitcoin's capacity on the developers' mailing list. He backed Segregated Witness, which Pieter Wuille had presented there as a soft fork that handles signatures separately and so "takes them outside the scope of the current blocksize limit".

    Network · 22:02 UTCSourceGregory Maxwell, "Capacity increases for the Bitcoin system.", bitcoin-dev mailing list (7 Dec 2015, 22:02:17 UTC)

  8. 23 Feb 2016

    Bitcoin Core 0.12 checks signatures with libsecp256k1

    Bitcoin Core 0.12.0 began checking transaction signatures with libsecp256k1 instead of OpenSSL, through a change by Pieter Wuille. The release notes said signature checks became over five times faster on x86_64 processors, and new blocks took less than half as long to validate.

    NetworkSourceBitcoin Core 0.12.0 release notes (published February 23, 2016; change #6954 by Pieter Wuille)

  9. 4 Jul 2016

    Relative timelocks (CSV) activate

    A soft fork bundling BIPs 68, 112 and 113 took effect at block 419,328. Its new CHECKSEQUENCEVERIFY rule lets coins be locked until a set time after they were received, a building block for payment channels such as the Lightning Network.

    Network · 23:16 UTCSee block 419,328SourceBitcoin Core source, CSVHeight = 419328 with the block hash

2016 to 2020

Miners earned 12.5 BTC a block until block 630,000, on 11 May 2020.

  1. 9 Jul 2016

    The second halving

    At block 420,000 the reward for mining a block fell from 25 to 12.5 bitcoin, the second halving.

    Network · 16:46 UTCSee block 420,000SourceBitcoin Core source, nSubsidyHalvingInterval = 210000

  2. 1 Aug 2017

    Bitcoin Cash splits off

    Bitcoin split in two when nodes following new rules, under the name Bitcoin Cash, accepted a block larger than Bitcoin's 1 MB limit. Anyone holding bitcoin before the split held the same amount of Bitcoin Cash.

    Network · 18:12 UTCSee block 478,558SourceBitcoin Cash UAHF technical specification (activation time 1501590000 = 1 Aug 2017 12:20 UTC; 8 MB)

  3. 1 Aug 2017

    The user-activated soft fork (BIP 148) takes effect

    BIP 148, the "user-activated soft fork" (UASF), took effect at block 478,484: nodes running it would reject any block that did not signal support for SegWit. Miners were already signalling after a compromise proposal, BIP 91, so no split followed from it.

    Network · 00:49 UTCSee block 478,484SourceBIP 148, Mandatory activation of segwit deployment (from midnight 1 August 2017 UTC)

  4. 9 Aug 2017

    SegWit locks in

    SegWit locked in at block 479,808 after every one of the 2,016 blocks in the previous two-week signalling period had signalled support, more than the 95% needed. The upgrade took effect two weeks later, at block 481,824.

    Network · 12:36 UTCSee block 479,808SourceCoinDesk, A New SegWit Lock-In Period Has Started and All Mining Pools Are Signaling (27 Jul 2017)

  5. 24 Aug 2017

    SegWit activates

    Segregated Witness (SegWit) took effect at block 481,824. It moves signatures into a separate part of the block, which fixes transaction malleability (the ability to change a transaction's ID before it confirms) and raises block capacity.

    Network · 01:57 UTCSee block 481,824SourceBitcoin Core source, SegwitHeight = 481824 with the block hash

  6. 8 Nov 2017

    SegWit2x is called off

    The backers of SegWit2x, a planned hard fork (a rule change that older software rejects) to double Bitcoin's block size, called it off about a week before it was due, saying they had not built enough consensus.

    NetworkSourceTechCrunch, "SegWit2x backers cancel plans for bitcoin hard fork" (8 Nov 2017)

  7. 23 Jan 2018

    Gregory Maxwell proposes Taproot

    Gregory Maxwell proposed Taproot on the bitcoin-dev mailing list: a design that lets coins with complex spending conditions, when everyone involved agrees, be spent in a way "indistinguishable from a normal one-party signature". It activated in November 2021.

    Network · 00:30 UTCSourceGregory Maxwell, "Taproot: Privacy preserving switchable scripting", bitcoin-dev mailing list (23 Jan 2018, 00:30:06 UTC)What happened

  8. 18 Sept 2018

    Inflation bug fixed in Bitcoin Core

    Bitcoin Core released version 0.16.3 to fix a bug (CVE-2018-17144) that could have let a miner create extra bitcoin by spending the same coins twice inside one block.

    Network · Until 20 SeptSourceBitcoin Core, Disclosure of CVE-2018-17144 (20 Sep 2018)

2020 to 2024

Miners earned 6.25 BTC a block until block 840,000, on 20 April 2024.

  1. 11 May 2020

    The third halving

    At block 630,000 the reward for mining a block fell from 12.5 to 6.25 bitcoin, the third halving.

    Network · 19:23 UTCSee block 630,000SourceBitcoin Core source, nSubsidyHalvingInterval = 210000

  2. 12 Jun 2021

    Taproot locks in

    Block 687,284 was the 1,815th in its two-week period to signal for Taproot, reaching the 90% needed under the "Speedy Trial" activation rules and locking in the upgrade. It took effect five months later, at block 709,632.

    Network · 12:04 UTCSee block 687,284SourceBitcoin Core 0.21.1 release notes, Taproot Soft Fork (Speedy Trial, 90% of a 2,016-block period)

  3. 3 Jul 2021

    Record fall in mining difficulty

    Bitcoin's mining difficulty fell 27.9% at block 689,472, the largest downward adjustment in its history, after China's crackdown knocked about half of the network's mining power offline.

    Network · 06:34 UTCSee block 689,472SourceHashrate Index, "Bitcoin Difficulty Adjustment Experiences 28% Drop, Largest Ever As Miners Exit China"

  4. 14 Nov 2021

    Taproot activates

    The Taproot upgrade took effect at block 709,632. It added Schnorr signatures and a new kind of output that reveals less about complex spending conditions, making them cheaper and more private.

    Network · 05:15 UTCSee block 709,632SourceBIP 341, Deployment section ("The deployment did activate at height 709632")What happened

  5. 16 Apr 2024

    Bitcoin Core 27.0 encrypts connections by default

    Bitcoin Core 27.0 turned on BIP 324 by default, so two nodes that both support it encrypt the connection between them. BIP 324, co-written by Pieter Wuille, makes it harder for an eavesdropper to tell where a transaction came from.

    NetworkSourceGitHub, Bitcoin Core 27.0 release (published 2024-04-16T20:16:23Z)

2024 to now

Miners earn 3.125 BTC a block until block 1,050,000, expected around June 2028.

  1. 20 Apr 2024

    The fourth halving

    At block 840,000 the reward for mining a block fell from 6.25 to 3.125 bitcoin, the fourth halving.

    Network · 00:09 UTCSee block 840,000SourceBitcoin Core source, nSubsidyHalvingInterval = 210000

  2. 10 Oct 2025

    Bitcoin Core 30.0 lifts the OP_RETURN limit

    Bitcoin Core 30.0 was released, raising the default limit on data in OP_RETURN outputs (unspendable outputs used to attach data to a transaction) from 83 bytes to 100,000 bytes, which in practice removes the cap.

    NetworkSourceBitcoin Core 30.0 release notes (published October 10, 2025)

  3. 29 Oct 2025

    Mining difficulty reaches a record

    Mining difficulty, a measure of how hard it is to find a block, rose 6.3% at block 921,312 to a record of about 156 trillion. As of October 2026 it had not been higher.

    Network · 10:14 UTCSee block 921,312Sourcemempool.space, block 921,312 (difficulty 155.97 trillion)

  4. 7 Feb 2026

    Largest mining difficulty drop since 2021

    Mining difficulty fell 11.16% at block 935,424, the largest drop since China's mining ban in 2021, after a US winter storm and falling prices led miners to switch off machines. It rose 14.7% at the next adjustment, on 19 February.

    Network · 13:56 UTCSee block 935,424Sourcemempool.space, block 935,424

  5. 11 Feb 2026

    Quantum-resistance proposal BIP 360 is merged

    BIP 360, a proposed new output type called Pay to Merkle Root (P2MR) that would not reveal public keys when coins are spent, was merged into the Bitcoin Improvement Proposals repository. It is meant as a first step towards protecting bitcoin from future quantum computers; merging records it for review and changes nothing on the network.

    Network · 20:38 UTCSourceGitHub, bitcoin/bips pull request #1670, BIP 360 - Pay to Merkle Root (P2MR)

  6. 19 Apr 2026

    Bitcoin Core 31.0 rebuilds the mempool

    Bitcoin Core 31.0 was released with "cluster mempool", a rebuilt system for holding unconfirmed transactions that groups related ones and ranks them by the fees miners would earn. It also added an option to send your own transactions only over Tor or I2P, hiding your IP address.

    NetworkSourceBitcoin Core 31.0 release notes (published April 19, 2026)

  7. 30 Jul 2026

    Coldcard wallets drained through a seed bug

    Attackers took about 594 bitcoin from about 500 Coldcard hardware wallets, using a firmware bug that made the devices' seeds (the secret words that back up a wallet) far easier to guess than intended. Galaxy Research later counted about 1,806 bitcoin taken across several waves.

    NetworkSourceCoinkite, Coldcard Security Advisory (30 Jul 2026, updated 1 Aug 2026)

  8. 8 Aug 2026

    BIP-110 supporters split onto a minority chain

    Nodes enforcing BIP-110, a proposed one-year soft fork (a tightening of the rules) to restrict non-financial data such as inscriptions, rejected block 961,632 because it did not signal support, and followed a rival block instead. Only about 2.5% of recent blocks had signalled for it, so the main chain kept going and the BIP-110 chain fell behind.

    Network · 19:35 UTCSee block 961,632SourceThe Block, Bitcoin's BIP-110 supporters split onto minority chain as main network pulls ahead (8 Aug 2026)

Ahead on the network

  1. 18 May 2027

    Block 1,000,000

    Bitcoin's millionth block. Nothing changes in how Bitcoin works; it's a round number.

    Network · EstimateBlock 1,000,000SourceWorked out from recent block times on mempool.space

  2. 3 Jun 2028

    Next halving

    At block 1,050,000, the new bitcoin miners earn for each block halves from 3.125 to 1.5625 BTC.

    Network · EstimateBlock 1,050,000

Every date ahead, in the calendar