The strike selection trade-off
Every strike represents a different balance between premium income and the probability of assignment. Lower strikes (closer to spot) pay more premium but have a higher chance of your crypto being called away. Higher strikes pay less but let you participate in more upside.
There is no universally 'best' strike — it depends on your market outlook, income target, and how attached you are to holding the underlying asset.
Using delta as a guide
Delta measures how much the option price moves for a $1 move in the underlying. For covered calls, delta also approximates the probability of the option expiring in-the-money (i.e., being assigned).
A delta of 0.30 means roughly 30% probability of assignment. Most income traders target the 0.20–0.35 delta range — enough premium to be meaningful, low enough assignment risk to be comfortable.
OTM% framework
A simpler approach: target strikes 3–8% out-of-the-money. At 3% OTM you collect more premium but give up less upside buffer. At 8% OTM you collect less but have more room before assignment.
In high-IV environments (BTC IV > 70%), you can go further OTM and still collect attractive premiums. In low-IV environments, you may need to go closer to the money to hit your income target.