Bitcoin Ahr999 Index

The Ahr999 index is a Bitcoin valuation gauge built for one decision: whether the current price is attractive for accumulating BTC through dollar-cost averaging (DCA). It was published in 2019 by the Chinese Bitcoin investor known as ahr999. It compares today’s price with two benchmarks at once: what a recent regular buyer paid, and where a long-term growth trend places Bitcoin for its age.

How the index is calculated

The index multiplies two ratios:

Ahr999 = (price ÷ 200-day DCA cost) × (price ÷ growth valuation)

• 200-day DCA cost is the average cost of buying BTC at regular intervals over the last 200 days. A ratio below 1 means the price sits under what recent accumulators paid.
• Growth valuation comes from a power-law model of Bitcoin’s age in days since the genesis block (January 3, 2009). In the standard version it is 10^(5.84 × log10(age in days) − 17.01). A ratio below 1 means the price trails that long-run trend.

Example: if BTC trades at 80% of its 200-day DCA cost and at 55% of its growth valuation, the index is 0.8 × 0.55 = 0.44. The price is cheap on both measures, so the product falls further than either ratio alone.

Reading the zones

The original method sorts each daily reading into one of three zones:

• Bottom: below 0.45, treated as a level for heavier buying.
• DCA zone: from 0.45 to 1.2, where routine accumulation fits the method.
• Wait: above 1.2, where the method suggests pausing purchases.

The index is calculated on daily closes. Because the value moves with price, a small swing near 0.45 can flip the zone back and forth over a few days.

Limits

The growth formula is a curve fitted to past prices, so its long-run trend is an assumption rather than a law. The index also gives no sell signal; its top zone only means “stop buying.” Readings from Bitcoin’s early years were extreme, which is why the all-time high runs into the hundreds.