Stock-to-flow (S2F)
A measure of scarcity: the existing stock divided by annual new production. A 2019 price model based on it became very popular, but was far off the mark and is no use for forecasts.
AlsoS2Fstock-to-flow modelS2F modelstock-to-flow ratio
On the learning path: Stage 2 · Step 2 – Halving & 21 million
Stock-to-flow (S2F) divides the existing stock of a good (stock) by the amount newly added each year (flow). The result tells you how many years today’s production would take to create the stock again – the higher, the scarcer. For gold, a figure of about 62 is quoted.[1]
Bitcoin in numbers
Since the 2024 halvingGlossaryHalvingEvery 210,000 blocks – roughly every four years – the number of new bitcoin per block is cut in half. The fourth halving, on 20 April 2024, reduced it from 6.25 to 3.125 BTC.On the learning path: Stage 2 · Step 2 – Halving & 21 million →In the glossary →, 3.125 BTC have been created per block; at roughly one block every ten minutes, that’s about 164,000 BTC a year.[2] With 20,093,887 BTC issued so far, that gives a stock-to-flow of just over 120 (our own calculation, as of September 2026). With the next halving, expected around March 2028, the value roughly doubles.
The price model – and why it failed
In March 2019, the anonymous analyst ‘PlanB’ derived bitcoin’s market value from stock-to-flow alone. For the period after the May 2020 halving, that came to around $1 trillion, or about $55,000 per BTC.[3],[1] For 2022, the model implied prices well above $100,000 – in reality, bitcoin fell below $16,000.[1]
The main objection: a price comes from supply and demand, but S2F only looks at supply. Besides, two quantities that both grow over time are easy to link statistically without one explaining the other.[1]
What this means for you: scarcity is a reasonable argument for Bitcoin, but no price forecast follows from it. Anyone who ‘calculates’ a price for you with a model is selling certainty that doesn’t exist. More in Myths & facts.
Related terms
These terms are closely connected.
- This termStock-to-flow(S2F)
- HalvingEvery 210,000 blocks – roughly every four years – the number of new bitcoin per block is cut in half. The fourth halving, on 20 April 2024, reduced it from 6.25 to 3.125 BTC.
- 21 million (Bitcoin’s supply cap)Under the network’s rules, there will never be more than just under 21 million bitcoin. The cap follows from the issuance schedule: new bitcoin per block halve every 210,000 blocks until none are created, around 2140.
- Store of valueOne of the three classic functions of money: it should keep its value over time so that you can save today and spend later. Whether bitcoin fulfils this role is disputed.
- Four-year cycle (halving cycle)An observed pattern in which the bitcoin price has risen sharply roughly in step with the halvings and then fallen steeply. It is based on only four runs and is not a reliable buy or sell signal.
Explained in depth
These articles go into more detail:
- Deep dive · Stage 2Digital scarcityWhy Bitcoin is considered scarce, how it compares with gold and why scarcity alone delivers neither a safe store of value nor a price forecast.
- Deep dive · Stage 2Myths & facts‘Only for criminals’, ‘anonymous’, ‘a safe hedge against inflation’? 12 common myths about Bitcoin – from sceptics and from fans – checked, with sources.
- Stage 2 · Step 2Halving & 21 millionWhy there will never be more than 21 million bitcoin: the issuance schedule, every halving by block height, MAX_MONEY in the code and the 2010 overflow bug.
More from „Money & economics“
Sources3 sources · 3 publishers
The superscript numbers in the text refer to these sources.
- Bitcoin Stock-to-Flow (S2F) Model Explained – CoinGecko, 22.07.2025 (accessed 28/09/2026)
- Controlled supply – Bitcoin Wiki (accessed 28/09/2026)
- Modeling Bitcoin's Value with Scarcity – PlanB (Medium), 22.03.2019 (accessed 28/09/2026)
This entry is for education only and is not investment, tax or legal advice.