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 1,420 (unconcentrated), and the single largest pool mined 24.9% 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 | 1,434 | 24.9% | 56.8% |
| Last month | 25 | 3 | 1,420 | 24.9% | 56.7% |
| Last 3 months | 26 | 3 | 1,509 | 28.1% | 57.9% |
| Last year | 34 | 3 | 1,538 | 29% | 58% |
Current pool shares (last month)
| # | Pool | Blocks | Share |
|---|---|---|---|
| 1 | Foundry USA | 1076 | 24.9% |
| 2 | AntPool | 826 | 19.11% |
| 3 | F2Pool | 547 | 12.66% |
| 4 | SpiderPool | 473 | 10.94% |
| 5 | ViaBTC | 385 | 8.91% |
| 6 | MARA Pool | 247 | 5.71% |
| 7 | SECPOOL | 168 | 3.89% |
| 8 | Luxor | 127 | 2.94% |
| 9 | OCEAN | 121 | 2.8% |
| 10 | SBI Crypto | 91 | 2.11% |
| 11 | Braiins Pool | 82 | 1.9% |
| 12 | Binance Pool | 63 | 1.46% |
| 13 | Unknown | 47 | 1.09% |
| 14 | ULTIMUSPOOL | 16 | 0.37% |
| 15 | BTC.com | 13 | 0.3% |
| 16 | WhitePool | 10 | 0.23% |
| 17 | Poolin | 9 | 0.21% |
| 18 | Innopolis Tech | 8 | 0.19% |
| 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.