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 23 identified mining pools, but it takes only 3 pools to control more than half the network — the Nakamoto coefficient. The HHI concentration index is 1,491 (unconcentrated), and the single largest pool mined 27.1% 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 | 18 | 3 | 1,478 | 25.6% | 57.6% |
| Last month | 23 | 3 | 1,491 | 27.1% | 58% |
| Last 3 months | 28 | 3 | 1,573 | 29.7% | 58.8% |
| Last year | 33 | 3 | 1,552 | 29.3% | 58.1% |
Current pool shares (last month)
| # | Pool | Blocks | Share |
|---|---|---|---|
| 1 | Foundry USA | 1173 | 27.15% |
| 2 | AntPool | 820 | 18.98% |
| 3 | F2Pool | 513 | 11.87% |
| 4 | SpiderPool | 447 | 10.34% |
| 5 | ViaBTC | 358 | 8.29% |
| 6 | MARA Pool | 237 | 5.48% |
| 7 | SECPOOL | 179 | 4.14% |
| 8 | Luxor | 146 | 3.38% |
| 9 | OCEAN | 125 | 2.89% |
| 10 | SBI Crypto | 94 | 2.18% |
| 11 | Binance Pool | 64 | 1.48% |
| 12 | Braiins Pool | 63 | 1.46% |
| 13 | Unknown | 37 | 0.86% |
| 14 | ULTIMUSPOOL | 22 | 0.51% |
| 15 | BTC.com | 15 | 0.35% |
| 16 | Poolin | 9 | 0.21% |
| 17 | Innopolis Tech | 7 | 0.16% |
| 18 | NiceHash | 4 | 0.09% |
| 19 | WhitePool | 3 | 0.07% |
| 20 | RedRock Pool | 3 | 0.07% |
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 also the mining-pool database.
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Last reviewed June 18, 2026.