interactive tool
Stock-to-Flow
Stock-to-flow is one number describing how scarce a thing is. Take the amount that exists — the stock — and divide it by how much is added per year — the flow. A higher ratio means new supply is a smaller fraction of what already exists.
Gold sits around 60. Silver, around 22. Bitcoin's issuance is cut in half every four years, so its ratio steps up at every halving. This tool lets you compute the number for any date and shows the comparisons side by side.
S2F describes scarcity. It does not predict price. The section at the bottom of this page steel-mans the critics.
Bitcoin · 2026-05-13
Block height
948,308
Stock (BTC)
20.03M
BTC mined
Flow (BTC/yr)
164.1k
next 365 days
S2F ratio
122
subsidy 3.125 BTC/block
| Asset | S2F ratio | Implied inflation |
|---|---|---|
| Bitcoin | 122 | 0.82% |
| Gold | 64.0 | 1.56% |
| Silver | 22.0 | 4.55% |
| USD M2 | 18.0 | 5.56% |
Stock-to-flow ratio over time (log scale)
Steel-manning the critics
In 2019 a pseudonymous analyst calling himself PlanB published a model plotting Bitcoin's price against its S2F ratio on a log-log scale. The fit was eerily good. The model became wildly popular and the price targets it implied — $100k by late 2021, then $288k by 2024 — were cited everywhere. It is worth taking the critiques seriously.
- The price model has failed empirically. Bitcoin's price diverged sharply below the trajectory in 2022 and has not consistently returned to the model's implied path. When a model misses, revising it after each miss is not how falsifiable models work.
- Correlation is not causation. Critics including Strato & Burakov (2022) showed that S2F's correlation with price is largely a function of two co-moving monotonic time series: both Bitcoin's S2F and Bitcoin's price rose over time. Run the same regression on any monotonically rising asset against time and you get a great fit.
- Scarcity is necessary, not sufficient. A perfectly scarce thing that nobody wants is worthless. Tin pennies are rare. Demand has to exist for scarcity to translate into value, and the S2F model says nothing about demand.
- Gold contradicts the model. Gold had a higher S2F than Bitcoin for most of Bitcoin's history yet did not appreciate at anything like Bitcoin's rate. If S2F drove price, similar S2F should produce similar returns. It doesn't.
What S2F does well: it describes one thing, precisely. Bitcoin is unusually scarce among monetary assets, and its scarcity is provable, scheduled, and not subject to discretion. That is interesting. It is not a price forecast.
How this is calculated. Bitcoin supply and issuance are deterministic from block height. We anchor at the four historical halvings (2012-11-28, 2016-07-09, 2020-05-11, 2024-04-20) and interpolate at 144 blocks/day between them. Past 2024 the projection assumes a steady 144 blocks/day average; the actual 2028 halving date will drift slightly.
Comparison data. Gold and silver S2F ratios are hand-curated central estimates compiled from World Gold Council and Silver Institute annual surveys. USD M2 S2F is computed as stock divided by annual change of the FRED M2SL series. In years when M2 contracted (2022–2023 post-COVID QT) the ratio is undefined and shown as a gap.
Source files: src/lib/s2f/supply.ts for the deterministic schedule, src/lib/s2f/comparisons.ts for the hand-curated reference series.