Stock-to-Flow — the model and where it broke.
PlanB's 2019 model priced Bitcoin from its scarcity: existing supply against new issuance, which doubles at every halving. Price tracked it for a decade, then fell away in 2022. This page shows the model and the gap.
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Price against the model since 2012
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Indicators describe where price sits relative to its own history. They are not forecasts and not financial advice. Past cycle behaviour is no guarantee of future cycles.
A decade on the line, then a break
The model steps up after every halving, as the 463-day average of stock-to-flow catches up with the new, lower issuance. Price last closed above it on January 2, 2022. After the 2024 halving the model climbed toward $830,000 while price stayed near $100,000, and the gap reached 0.07× in June 2026. The fit here uses PlanB's published constants on our own supply estimate.
What it read at past tops and bottoms
| DATE | BTC CLOSE | PRICE / MODEL | MODEL PRICE | |
|---|---|---|---|---|
| 2013 top | Dec 4, 2013 | $1,132 | 25.22× | $44.89 |
| 2015 bottom | Jan 14, 2015 | $171.41 | 0.85× | $201.21 |
| 2017 top | Dec 17, 2017 | $18,953 | 8.19× | $2,314 |
| 2018 bottom | Dec 15, 2018 | $3,180 | 0.63× | $5,062 |
| April 2021 top | Apr 13, 2021 | $63,564 | 4.76× | $13,362 |
| November 2021 top | Nov 8, 2021 | $67,559 | 1.76× | $38,283 |
| 2022 bottom | Nov 21, 2022 | $15,766 | 0.22× | $71,565 |
| 2025 top | Oct 6, 2025 | $124,728 | 0.28× | $438,330 |
| Latest close | Sep 27, 2026 | $84,457 | 0.10× | $829,565 |
Get pinged when it crosses your level
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Fair questions, straight answers
PlanB's 2019 model of Bitcoin's price from its scarcity. Stock-to-flow is the existing supply divided by the new supply issued each year. It doubles at every halving, and PlanB fitted market cap to it as e^14.6 × SF^3.3, with SF averaged over 463 days.
No. Price tracked it roughly until 2021, closed above it for the last time on January 2, 2022, and has sat far below it since. The model puts fair value near $830,000 today while price trades at about a tenth of that. Even the 2025 top reached only 0.28× the model.
It shaped how a whole cycle of investors thought about Bitcoin, and it's still one of the most searched Bitcoin models. The ratio here shows how far price has fallen from it, which says as much about the model as about price.
From Bitcoin's issuance schedule: the exact supply at each halving, interpolated between halvings, and 144 blocks a day at 3.125 BTC since April 2024. It lands within a few thousand BTC of reported circulating supply.