Mining charts/Mining Diversity Index

Mining Diversity Index

Herfindahl-Hirschman Index (HHI) measuring mining concentration. Below 1000 is competitive, above 1800 is concentrated

Linear: equal distances are equal differences, so 0 to 100 takes the same height as 100 to 200. Logarithmic: equal distances are equal ratios, so each step up is a multiplication, and only positive values can be drawn. A series spanning several orders of magnitude, such as price or difficulty, shows its early years on a log axis and flattens into a line along the bottom on a linear one.

Short ranges plot one point per block, about one every ten minutes. Longer ranges plot one point per day, computed from every block in that day. How it is computed depends on the chart: some average, some total the day up, some are a ratio of the day's sums, and each chart says which. Either way a brief spike inside a day is smoothed away.

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Key factsCalculated from the points currently plotted, so they follow the range you pick. Zooming with the slider changes only what you see, not these.

over selected range

OverlaysExtra context drawn on top of the chart. Event markers are vertical lines at dated moments; a comparison series is a second set of numbers on its own axis at the right.

Event markers

Every 210,000 blocks, roughly every four years, the block subsidy halves. Fees are the other part of what a miner collects and do not halve with it. Four halvings have happened so far.

A BIP is a Bitcoin Improvement Proposal: a design document for a change to the protocol. These lines mark the dates that proposals such as SegWit and Taproot became active on the network.

Releases of Bitcoin Core, the software most nodes run. A release does not change consensus rules by itself, but it often changes what transactions a node will relay, which can show up in these charts.

Dated moments outside the protocol that moved the numbers: exchange failures, country-level bans, the first Ordinals inscriptions.

Comparison series

The BTC price in US dollars, drawn on its own axis on the right. Sampled every 4 days, which is all the source provides for the full history, so a range shorter than that cannot draw it. Price crosses six orders of magnitude, so it usually wants the logarithmic setting beside it.

The total size of the block chain on disk, growing as blocks are added. An archival node keeps every byte of it; a pruned one verifies the same blocks and then discards the old ones.

one at a time: they share the right axis

RelatedCharts measuring the same thing or covering the same part of the network, for reading this one in context.

Empty Blocks Empty Blocks by Pool Hash Rate Difficulty Adjustment

Get this data

CSV and JSON take the selected range without overlay series. PNG captures the chart as it looks now.

About this metric

Definition

One number for how concentrated block production is. It is the Herfindahl-Hirschman Index, borrowed from competition economics: square each pool's percentage share and add them up. Two pools at 50% each score 5,000; a hundred pools at 1% each score 100. It rises faster than a share does, which is the point, because concentration is what it is built to be sensitive to.

How it is measured

Computed from the shares of blocks in the selected range, by pool, after excluding blocks with no identified pool and renormalising the rest. So it describes identified block production and not ownership of hash rate, and OCEAN template miners count as separate participants because that is how they appear in the coinbase. The 1,000 and 1,800 boundaries and their colours are the conventional reading from antitrust practice, not validated thresholds for Bitcoin. A monopoly scores 10,000, perfectly distributed mining scores near 0. Below 1,000 (green): competitive market. 1,000-1,800 (yellow): moderate concentration. Above 1,800 (red): high concentration, meaning a small number of pools control most of the hashrate. Unknown miners are excluded from the calculation.

Measured from my own Bitcoin node. Methodology