Bitcoin Mining Pool Centralization: Nakamoto Coefficient & HHI Tracker

How concentrated is Bitcoin mining? Nakamoto coefficient, HHI and per-pool hashrate share across time windows.

Quick answer

Over the last month, Bitcoin's hashrate was spread across 25 identified mining pools, but it takes only 3 pools to control more than half the network — the Nakamoto coefficient. The HHI concentration index is 1,418 (unconcentrated), and the single largest pool mined 24.8% of blocks. Lower Nakamoto and higher HHI both mean more centralization.

Solo and decentralized-template mining (DATUM, Stratum V2 job declaration) push the Nakamoto coefficient up. Full data — every window, free to download under CC BY 4.0.

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Concentration by time window

Window	Pools	Nakamoto	HHI	Top pool	Top 3
Last week	17	3	1,447	25.1%	56.9%
Last month	25	3	1,418	24.8%	56.6%
Last 3 months	26	3	1,510	28.1%	57.9%
Last year	34	3	1,538	29%	57.9%

Current pool shares (last month)

#	Pool	Blocks	Share
1	Foundry USA	1075	24.83%
2	AntPool	830	19.17%
3	F2Pool	546	12.61%
4	SpiderPool	476	11%
5	ViaBTC	383	8.85%
6	MARA Pool	247	5.71%
7	SECPOOL	167	3.86%
8	Luxor	127	2.93%
9	OCEAN	121	2.8%
10	SBI Crypto	94	2.17%
11	Braiins Pool	83	1.92%
12	Binance Pool	62	1.43%
13	Unknown	48	1.11%
14	ULTIMUSPOOL	17	0.39%
15	BTC.com	13	0.3%
16	WhitePool	10	0.23%
17	Poolin	9	0.21%
18	Innopolis Tech	8	0.18%
19	NiceHash	7	0.16%
20	RedRock Pool	2	0.05%

Method: The Nakamoto coefficient is the fewest pools whose combined share exceeds 50% of blocks — the smaller it is, the easier a majority coalition. HHI sums the squared percentage shares (US DOJ guide: <1500 unconcentrated, 1500-2500 moderate, >2500 highly concentrated). Pool attribution from mempool.space is a proxy based on coinbase tags (see which tag each pool stamps). See also the mining-pool database.

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Last reviewed June 18, 2026.