The stock-to-flow ratio is a scarcity metric that compares the existing quantity of an asset (“stock”) with the amount added over a period, typically one year (“flow”). A higher ratio means the stock is large relative to new supply, implying slower supply growth at current production or issuance rates.

stock-to-flow (S2F), stock/flow ratio, inventory-to-production ratio

Stock-to-flow is a compact way to describe an asset’s supply-side dilution and the degree to which new supply can change the total outstanding quantity over time. For monetary commodities and some digital assets, where durability and long-lived inventories matter, the ratio helps compare how quickly supply expands under “normal” production or issuance conditions. It can also inform market-structure and risk discussions. In markets where new supply is highly responsive to price (or policy), changes in the “flow” component can alter scarcity dynamics, affect expectations about future supply growth, and influence how investors frame long-term viability of an issuance regime.

The intuition behind stock-to-flow comes from commodity analysis, where analysts compare above-ground inventories to annual production to characterise scarcity and replenishment speed—especially for durable, storable commodities such as precious metals. In the 2010s, the same framing was adapted to certain cryptoassets because on-chain issuance schedules make “flow” mechanically defined and, in some protocols, discretely change over time (for example, periodic reductions in issuance).

At a high level, stock-to-flow is a ratio of two quantities measured in the same units.

• Stock (S)
  The total existing quantity considered part of supply. The precise definition depends on the asset:
  • Precious metals: often estimated above-ground stock (bars, coins, jewellery, and other held inventories), which can be difficult to measure precisely.
  • Cryptoassets: typically circulating supply (units issued and not provably burned). Some analyses adjust for estimated lost coins or illiquid holdings, but these adjustments introduce model risk.
• Flow (F)
  The net new quantity added over a chosen period, most commonly one year:
  • Commodities: annual mine production is often used; depending on the commodity, analysts may also consider recycling or net additions if destruction/consumption is relevant.
  • Cryptoassets: net issuance over the period (newly minted units minus any protocol-level burns, if applicable).
• Time window and consistency
  Stock-to-flow is usually computed on an annualised basis to align with production and issuance reporting. Using shorter windows is possible, but it increases sensitivity to seasonality, shocks, and measurement noise.
• Interpretation
  The ratio is dimensionless. Under a simplified “steady flow” assumption, it can be read as the number of years of current flow required to equal the existing stock. Equivalently, it is the inverse of the proportional supply growth rate over the same window.
• Where it is most meaningful
  Stock-to-flow tends to be most interpretable for assets with:
  • high durability (stock persists rather than being rapidly consumed), and
  • measurable inventories and production/issuance.
    For consumables with rapid turnover (where “stock” is small because most output is consumed), the ratio can be low without implying that the asset is economically “non-scarce.”