Bitcoin Stock-to-Flow Model
The stock-to-flow ratio (S2F) divides the bitcoins in existence by the coins issued over the last year. Halvings cut the issuance in half, so the ratio roughly doubles after each one. PlanB's model turns the ratio into a price with a 2019 regression; the chart compares it with the actual daily close. Supply is estimated from the issuance schedule, not read from the blockchain.
On 3 Oct 2026 Bitcoin's estimated supply is 20.09M BTC and about 164,250 BTC were issued over the last 365 days, a stock-to-flow ratio of 122.3. PlanB's model, ln(market value) = 3.3 × ln(S2F) + 14.6, puts the price at $844,195; Bitcoin ($84,637) is 0.10× that. Since 17 Aug 2017 it closed below the model on 70% of days. The block subsidy is 3.125 BTC; each halving roughly doubles the ratio over the following year. The model was fitted on 2009–2019 data and is not a forecast; fees are not part of the flow.
Bitcoin Stock-to-Flow model chart
17 Aug 2017 – 3 Oct 2026 · log price · CSVBTC price S2F model price (PlanB)
Supply and issuance are estimated from the halving schedule, not read from the blockchain; the price history starts on 17 Aug 2017. The model line is PlanB's 2019 regression: a model, not a forecast. The chart plots every 7th day to stay light; the CSV has every day. Not financial advice: these pages describe what each indicator showed in past cycles and predict nothing.
Halvings and the issuance schedule
block subsidy halves every 210,000 blocks| Halving | Block | Subsidy after | Supply at the halving |
|---|---|---|---|
| 28 Nov 2012 | 210,000 | 25 BTC | 10.50M BTC |
| 9 Jul 2016 | 420,000 | 12.5 BTC | 15.75M BTC |
| 11 May 2020 | 630,000 | 6.25 BTC | 18.38M BTC |
| 20 Apr 2024 | 840,000 | 3.125 BTC | 19.69M BTC |
| next (est. 2028) | 1,050,000 | 1.5625 BTC | 20.34M BTC |
Stock-to-Flow FAQ
How is the stock-to-flow ratio calculated here?
Stock is the estimated number of bitcoins in existence at the end of each UTC day; flow is the number issued over the previous 365 days. Both come from the issuance schedule: 50 BTC per block, halved every 210,000 blocks. The block height of a date is interpolated between the genesis block (3 January 2009) and the halvings of 28 November 2012, 9 July 2016, 11 May 2020 and 20 April 2024, and runs at 144 blocks a day after the last one. Real block times vary, so the figures are close estimates, not blockchain data.
What is the S2F model price?
The regression PlanB published in “Modeling Bitcoin's Value with Scarcity” (March 2019): ln(market value in USD) = 3.3 × ln(S2F) + 14.6. We divide that market value by the estimated supply to get a price per coin. The coefficients are PlanB's, fitted on 2009–2019 data; we do not refit them.
Is the Stock-to-Flow model a forecast?
No. It is a model of past prices, and since 2021 the price has spent long stretches far below it. It ignores demand entirely and leaves out transaction fees. Read it as one way past cycles lined up with the halvings, not as a price target.
Where does the price data come from?
Daily closing prices (00:00 UTC) of Bitcoin from exchange public APIs: Binance spot BTCUSDT from 17 Aug 2017. Moving averages start once enough days of history have passed. The data refreshes every few hours, and today's close is the latest price so far. Each chart's data is free to download as CSV.
Is this a buy or sell signal?
No. These indicators describe how the price moved against its own averages in past cycles, and Bitcoin has had only a handful of cycles, so any pattern rests on very few examples. Nothing here is financial advice.