Max loss first
For a long call or put, max loss is about the premium paid plus fees if you hold to worthless. For a debit spread, it is about the net debit plus fees. For a credit spread or iron condor, it is about the width minus credit plus fees. If you cannot write that number down, you cannot size.
Risk lab payoffs on /t/{asset}/strategy are educational shapes, not live fills. Use them to see which input (spot, IV, time) actually hurts you, then apply your own dollars or coin.
Notional is a vanity metric
A 0.01 BTC call can sit on large notional and still be a small premium risk if you are long. A short 0.01 BTC call can require margin that dwarfs the premium. Always separate: premium at risk, margin at risk, and notional controlled.
Portfolio margin can make a short look cheap until a vol spike or a gap. Liquidation risk on crypto venues is not theoretical — see the liquidation guide.
Inverse versus linear bankroll
If the option P&L is in BTC, a winning coin-margined short in a crash can still leave you poorer in USD if BTC fell enough. If you think in dollars, convert. If you think in coin, stay consistent and do not mix linear USDT books into the same “one BTC” bucket.
Open interest and volume on Match stats are useful for venue choice, not for position size.
A simple sizing rule that is not magic
Many desks cap a single defined-risk idea at a small fraction of liquid net worth (for example low-single-digit percent of risk capital) and cap correlated ideas as one book. That is a starting heuristic, not advice. The point is: correlated BTC-ETH-SOL vol shorts are one risk, not three.
Add spread costs. Cheap OTM wings can double the “premium” you thought you paid once you cross the market twice.
When not to size up
Mock or partial feeds. Empty wings. Unclear geo access. Event tenors you have not mapped. Undefined shorts you cannot hedge because perps are chaotic. If any of those are true, size is zero until they are not.
OptionsMatch alerts on this device can remind you of levels; they do not manage risk for you.
Practice this on OptionsMatch
Build the structure in /t/btc/strategy, note max loss on the payoff, then look at /t/btc/calculator for T+0 intuition. Venue margin models live on /venue profiles — still verify on-exchange.
Not financial advice. Sizing is personal and jurisdiction-specific.