What stock-to-flow actually measures

Stock-to-flow (S2F) compares how much of an asset already exists (the stock) with how much new supply is added each year (the flow). Divide the first by the second and you get the number of years of current production it would take to reproduce the existing supply.



A high S2F means annual new supply is only a small fraction of what already exists — so no ordinary boom in production can flood the market. That supply-side inertia is why assets with high S2F have historically been used to store value. It is a measure of supply hardness, which — as crypto4me’s analysts frame it — captures how resistant an asset is to inflation, not how much it is worth.

The headline number

Using the latest figures from the World Gold Council (WGC) and U.S. Geological Survey (USGS): gold mine production hit a record of roughly 3,672 tonnes in 2025 against an above-ground stock of about 216,265 tonnes — an S2F of about 59 years.

Bitcoin, after its April 2024 “halving,” now issues 3.125 coins per block — roughly 164,250 per year — against a circulating supply near 19.8 million. That is an S2F of about 120 years, a little over double gold. On this metric, and at this moment, Bitcoin is the hardest of the major monetary assets.

How hard is each asset to inflate, and what is it for?

The real story: 2024 was the crossover

The “twice as scarce” figure is not a permanent fact — it is the result of a single event. Bitcoin’s issuance is cut in half roughly every four years, so its S2F doubles at each halving, while gold’s stays broadly flat. Line the two up and a clean pattern appears:

Bitcoin’s stock-to-flow doubles at every halving; gold’s stands still

In other words, the 2024 halving is the moment Bitcoin’s supply hardness went from level with gold to double it. If the schedule holds and gold’s production stays near today’s levels, the 2028 halving will push Bitcoin to roughly four times gold. This is the one place where Bitcoin’s design produces something no physical commodity can: a supply rate that only ever falls, on a date known years in advance.

Where S2F stops being useful

S2F is a good description of supply. On the other hand, it is a poor crystal ball:

– It does not predict price. The popular “S2F price model” that projected Bitcoin’s value from this ratio broke down badly after 2021. High hardness can coexist with falling prices. S2F explains the supply side; demand, liquidity and sentiment set the price.

– It is a snapshot, not a constant. Quote it with a date. Before April 2024 the very same metric said Bitcoin and gold were equally hard.

– It ignores demand and volatility. A hard-to-inflate asset can still swing 70% in a year. Scarcity is not stability. Two different kinds of certainty. Gold’s S2F rests on thousands of years of accumulated, nearly indestructible stock. Bitcoin’s rests on an algorithm and about sixteen years of social consensus that the 21-million cap will be honoured. Both are strong; they are not the same thing.

– Lost coins cut both ways. An estimated 3–4 million BTC are likely lost forever, which arguably raises effective scarcity — but the exact figure is unknowable, so we treat it as a caveat, not a headline.

What the number still gets right

Stripped of hype, S2F captures one genuine structural difference. For every physical commodity, a high price eventually pulls in capital, new mines and more supply — the classic boom-and-bust of the mining cycle. Bitcoin severs that link entirely: when its price rises, more miners compete, but the network simply raises its difficulty so that the same number of coins is issued on schedule. Extra investment turns into security, not new supply. A perfectly inelastic issuance schedule, immune to price, is the one thing S2F is exactly right to reward.

A fair word on risk

This is not a one-sided case. Bitcoin carries real drawbacks a store-of-value buyer should weigh: price volatility, the energy intensity of mining, the risk of losing private keys, and a still-unsettled regulatory picture. Gold and the industrial commodities carry their own: storage and insurance costs, the risk of confiscation or blockade in transit, and — for the industrial metals — the constant threat of being engineered out and replaced. Scarcity is one input into an allocation decision, not the whole of it.

The takeaway

Is Bitcoin twice as scarce as gold? By stock-to-flow, in 2025, yes — roughly. It is the hardest major monetary asset on the single most-cited supply metric, and the 2024 halving is what put it there. But “harder to inflate” is not “worth more” or “safer.” The honest headline is narrower and, we think, more interesting: for the first time, an asset’s scarcity is set by arithmetic rather than geology.

Data sources: World Gold Council (WGC) and U.S. Geological Survey (USGS), 2025 data. Stock-to-flow figures are approximate and change at each Bitcoin halving. This note is for analytical and informational purposes only and does not constitute investment advice. Crypto assets are volatile and you may lose your entire investment.