The four supply numbers, and why they disagree
Circulating, total, maximum and fully diluted supply answer four different questions, which is why data sources rarely publish the same figure.
Most digital assets carry more than one supply figure, and the figures rarely agree. The four in common use are circulating supply, total supply, maximum supply, and the planned supply used in fully diluted arithmetic. They differ because each answers a different question: what can move today, what exists today, what can ever exist, and what the issuance plan implies for later.
What each number counts
Circulating supply is an estimate of the units that exist and are free to move. It excludes units still held under a lock-up contract, units never issued, and, at most data sources, units held by the issuing organization for future distribution. It is the denominator behind market capitalization, and it is genuinely an estimate: deciding which balances are free to move is a classification judgment, not a reading taken off the chain.
Total supply counts every unit that has been created and still exists, whether or not it can move today, minus units verifiably destroyed in a token burn. A wide gap between total and circulating almost always means locked allocations: team and early investor tranches under vesting, ecosystem incentive pools, or a protocol treasury that has not yet spent what it holds.
Maximum supply is the ceiling written into the protocol's own rules. Bitcoin has one: the block subsidy halves on a fixed block schedule, so the total approaches a limit slightly under 21 million and never passes it. Many assets have no ceiling at all, because their emission schedule continues indefinitely. An empty maximum-supply field means the protocol sets no cap, which is different from the figure being unknown, and the two cases are often displayed identically.
The fourth number is the least standardized. Fully diluted valuation needs a unit count to multiply by price, and different sources use maximum supply, total supply, or a projection of supply at some future date. The three give different answers for the same asset on the same day.
| Number | What it counts | Set by | Moves when |
|---|---|---|---|
| Circulating | Units judged transferable now | Data provider methodology | Unlocks, issuance, burns, reclassification |
| Total | All units in existence, locked or not | The ledger, minus burns | New issuance and destruction only |
| Maximum | Protocol ceiling, if one exists | Protocol rules | Almost never, and only by consensus change |
| Fully diluted base | Assumed eventual supply | Whoever computes the ratio | When the assumption changes |
Where the disagreements come from
The largest source is classification. If a foundation holds a quarter of the units in a wallet it controls with no contractual lock, one provider may treat those units as circulating because nothing prevents their movement, and another may exclude them because the foundation has stated it will not sell. Both readings are defensible. Neither is verifiable from the ledger alone.
Burn accounting is the second source. Some projects destroy units by sending them to an address with no known private key, which leaves the balance visible on the chain forever; others call a function that reduces the recorded supply directly. Providers differ on whether the first case is subtracted from total supply. The units are equally unusable either way, but the published number is not the same.
Representations on other chains create double counting. A wrapped token is a claim issued on a second chain against units immobilized on the first. Adding the balances together counts the same economic unit twice, and naive aggregation across chains does exactly that.
Supply figures also include units nobody can reach. Coins whose keys are lost are indistinguishable from coins whose owner is patient, so key loss quietly overstates every supply number by an amount no one can measure. Estimates of the affected quantity exist; none is authoritative.
A final source is the design of the asset itself. Some tokens rebase, adjusting every holder's balance by a common factor so that the unit count changes without anyone transacting; for those assets a supply figure means nothing without the adjustment history beside it. Stablecoins expand and contract with deposits and redemptions, so their supply is a running record of capital entering and leaving an instrument rather than the output of a schedule, and scarcity vocabulary applied to it describes nothing.
Which number belongs in which calculation
Market capitalization uses circulating supply, because it is meant to describe the value of what trades. Fully diluted valuation uses a larger base, so it always produces a number at least as large. Comparing an asset's market capitalization to another asset's fully diluted valuation is an error that survives longer than it deserves to, because both figures are labeled in the same currency and look comparable.
Two derived readings do most of the work. Pending supply expresses units not yet in circulation as a share of the eventual base, and FDV to market cap expresses the same idea as a multiple. A ratio near one means the supply is largely issued; a much higher ratio means most of the eventual units have yet to reach the market. Neither reading is a verdict on the asset, and neither says anything about when the remaining units arrive, who holds them, or what they cost their current holders.
How to check a supply figure rather than accept it
For a contract-based token, the total supply is a public function call, and the balances of named treasury and vesting contracts are readable. For a chain's native unit, the issuance rules are in the client software, and the running count is derivable from block history. Where a figure cannot be reproduced that way, it rests on a stated policy, and the policy is the thing to read.
Supply numbers also get revised. Providers reclassify wallets and correct historical series, so a figure recorded for a past date may not match today's version of that same date, and a reclassification can produce a step in the series that resembles a supply event without any units having moved. Two habits make the figures usable in spite of this. The first is to check which base any displayed ratio uses, because the same ratio computed on circulating and on eventual supply produces two different numbers carrying the same label. The second is to read a supply figure as a quantity of units first and as a currency amount second, since a dollar-denominated supply figure moves with price and can fall while the unit count rises.
The supply pages on this site show all four figures side by side with the classification rules applied, and methodology states which base each ratio uses. The next lesson in this track covers how new units are created in the first place, and who receives them.