A US listed equity option controls 100 shares. That 100 is so universal it stops being a number you think about — it is baked into every mental shortcut about premium, notional and exposure.
Crypto has no such constant, and that is the point. The multiplier is a property of the individual product, not of the market.
Three different answers on one venue
The coin-settled BTC and ETH contracts are one coin each. The linear, USDC-settled altcoin options are not: an AVAX contract covers 100 AVAX, and a TRX contract covers 10,000 TRX.
So a trader who learned “crypto options are one coin” from the BTC chain and applied it to the TRX chain is out by four orders of magnitude. The correction for the equity habit is not a different constant — it is that there is no constant.
Where it goes wrong
Notional. Contract count means nothing without the multiplier. Comparing open interest between two chains by counting contracts compares quantities in different units.
Dollar gamma. A dealer map multiplies open interest by gamma and by a multiplier. Get the multiplier wrong and the shape of the map survives while every magnitude is fiction — worse than an obvious error, because the picture still looks right.
Cross-book comparison. This is why figures should be computed and reported per book rather than aggregated, the same argument as in settlement currency decides what the numbers mean.
The other specs that vary the same way
Strike increments are coarser relative to price than on a liquid equity, which affects how precisely a wall can sit. Tick sizes are quoted in the settlement currency. And settlement type — coin or stablecoin — changes the payoff shape itself, not just the currency, per inverse options.
The habit that prevents all of it
Read the contract specification once per product, and write the multiplier down before computing anything. It is a thirty-second check protecting every downstream number, and it is exactly the sort of error that survives review — because nobody re-derives a constant they believe they already know.