The First Bitcoin Halving: Block 210,000 on 28 November 2012

On 28 November 2012 at 15:24:38 UTC, Bitcoin mined block 210,000 and the miner subsidy dropped from 50 BTC to 25 BTC. That was the first subsidy halving — the moment the issuance schedule written into the protocol actually cut new-coin creation in half. The anniversary falls every 28 November. This year it is three weeks from publication day.

No soft fork, no vote, no central bank. Every full node already knew the rule: after every 210,000 blocks, right-shift the subsidy.

The first halving at a glance

Date	28 Nov 2012
Block height	210,000
Block hash	000000000000048b95347e83192f69cf0366076336c639f9b7228e9ba171342e
Header timestamp	15:24:38 UTC (Unix 1354116278)
Subsidy before	50 BTC per block
Subsidy after	25 BTC per block
Transactions in the block	457
Coinbase total	38.56295554 BTC (25 BTC subsidy + ~13.56 BTC fees)
Pool / finder	Slush's Pool; miner handle laughingbear
Supply just before	10,500,000 BTC — 50% of the 21 million target
Interval in the code	nSubsidyHalvingInterval = 210000

What a halving actually is

Bitcoin creates new coins only in the coinbase of each block. The function that sets that amount starts at 50 BTC and halves it every 210,000 blocks:

int halvings = nHeight / consensusParams.nSubsidyHalvingInterval;
CAmount nSubsidy = 50 * COIN;
nSubsidy >>= halvings;

nSubsidyHalvingInterval is hard-coded to 210,000 in Bitcoin Core's consensus parameters (src/kernel/chainparams.cpp). Integer height division means block 209,999 was still in era 0 (50 BTC). Block 210,000 is the first block of era 1 (25 BTC). Later eras follow the same math: 420,000 → 12.5, 630,000 → 6.25, 840,000 → 3.125.

At roughly one block every ten minutes, 210,000 blocks is about four years. The first era ran longer in calendar time than a neat four-year mark — about 1,425 days from genesis to block 210,000 — because early hashrate and difficulty did not match today's cadence.

The controlled-supply schedule is why Bitcoin approaches, but never quite reaches, 21 million coins. Each era issues half as many new coins as the one before: 10.5M, then 5.25M, then 2.625M, and so on.

What happened on 28 November 2012

Bitcointalk was already running a long "Happy halving day" thread when the block landed. Within minutes a separate thread titled 210000 block found posted the explorer stats: height 210000, timestamp 2012-11-28 15:24:38, relayed by Slush, block reward 25 BTC, and unusually large fees of about 13.56 BTC.

Forum users noticed the fee spike immediately. People had been stuffing transactions into the mempool to get into the historic block — some with fees of 0.1, 0.5, even 1 BTC or more. One reply summed it up: people wanted to be part of the glory. Blockchain.info put fireworks on the block page. Another poster wrote that it felt weird seeing the coin totals end in a 5 instead of a 0.

Slush's Pool found the block. The contributing miner posted as laughingbear: new to the forums, mining for less than a week on an average GPU, and calling it the first block they had ever found. The Bitcoin Wiki records the hardware as a Radeon HD 5800-series card. Slush confirmed the find on the pool and sent a small bonus. Contemporary explorers still show the coinbase tagged /slush/; modern explorers often attribute the same pool under its later Braiins name.

The network did not stall. Hashrate did not collapse on the spot. The rule that had lived in the source since day one simply executed.

How to check block 210,000 yourself

You do not have to take our word for it. Open a public explorer and look up the height or the hash.

1. Go to mempool.space/block/210000 or blockstream.info/block/210000.
2. Confirm the hash starts with 000000000000048b95347e83192f69cf…1342e.
3. Confirm the timestamp: 2012-11-28 15:24:38 UTC.
4. Open the coinbase (first transaction). The output value is 38.56295554 BTC — that is the 25 BTC subsidy plus the fees collected in that block, not a 50 BTC reward.
5. Optionally open block 209999 next door. Its coinbase still reflects the 50 BTC subsidy era.

Same habit as looking up genesis or the pizza transaction: see Bitcoin history yourself on a block explorer. Dated moments belong on a chain you can re-check.

Where the first halving sits on the early timeline

The first halving is the first big supply event after Bitcoin's chaotic opening years:

• 3 Jan 2009 — genesis block (50 BTC subsidy begins)
• 12 Jan 2009 — first person-to-person payment in block 170
• 22 May 2010 — Pizza Day
• 15 Aug 2010 — the value overflow incident, when the 21 million sanity check was hardened in code
• 28 Nov 2012 — first subsidy halving at block 210,000

The early stretch through 2010 is covered in our Bitcoin history timeline 2008–2010. 28 November belongs on the recurring list in our Bitcoin anniversaries calendar alongside Whitepaper Day (31 Oct), Genesis Day (3 Jan), and Pizza Day (22 May).

Later halvings followed the same 210,000-block clock: 9 Jul 2016 (block 420,000), 11 May 2020 (block 630,000), and 20 Apr 2024 (block 840,000). The first one proved the schedule was real.