Setting the Strike and Expiration on a Covered Call
Setting up a covered call comes down to one trade-off worked through two dials: the strike you sell at and the date it expires. Both turn the same balance (how much premium lands in your account today against how much of the stock’s future gain you hand to the buyer), so this page treats them as the single decision they are, not two topics. It is about covered calls only: calls on shares you already own and would be content to sell at the strike. (Cash-secured puts use a mirror-image version of the same logic, and they are a separate decision; see the link at the end.)
The whole decision comes down to one trade-off, applied with one precondition. The precondition first: a covered call only makes sense on shares you’d be happy to hold and willing to part with at the strike you pick. If a strike is a price you would not actually be glad to sell at, it is the wrong strike no matter how much premium it pays. With that fixed, the trade-off is simple to state and is the whole game: more premium today means giving up more upside and accepting higher odds your shares get called away. The strike sets where that balance lands and the expiration tunes it, but it is one balance either way.
A worked example: three strikes on the same stock
Section titled “A worked example: three strikes on the same stock”Say you own 100 shares of a stock trading at $170, and you’d be glad to sell anywhere from here up to about $185. You look at calls expiring in 35 days and see three you could write:
| Strike | Position vs. price | Premium (per share) | Premium collected | Upside kept to strike |
|---|---|---|---|---|
| $175 | Slightly out of the money | $2.80 | $280 | $500 ($170 → $175) |
| $180 | Further out of the money | $1.50 | $150 | $1,000 ($170 → $180) |
| $185 | Far out of the money | $0.70 | $70 | $1,500 ($170 → $185) |
Read the table left to right and the trade-off is right there. The $175 call pays the most premium, $280, because it sits closest to the current price and so is the most likely to finish in the money and take your shares. The $185 call pays the least, $70, but leaves you $1,500 of room to run before your gain is capped. The $180 call splits the difference. None of these is “best” in the abstract. The right one is the strike whose sell price you would genuinely be happy with, and the premium follows from that choice rather than driving it.
These premiums are illustrative, shaped to historical norms for an out-of-the-money call on a roughly $170 stock at moderate volatility. The actual numbers on your screen will differ with the stock, the volatility, and the day. They are here to show the shape of the trade-off, not a rate to expect.
How the strike sets the trade-off
Section titled “How the strike sets the trade-off”Two forces move in opposite directions as you raise the strike.
Premium falls as the strike rises. A call is worth more to the buyer the more likely it is to pay off. A strike close to the current price has a real chance of finishing in the money, so the buyer pays up for it; a strike far above the price is a long shot, so it costs little. That is why the $175 call collected four times what the $185 call did. For the full mechanics of how a premium is priced, see the Greeks.
Upside kept rises as the strike rises. A covered call caps your gain at the strike. Above it, every additional dollar the stock climbs goes to the buyer, not to you. A $175 strike caps you after a $5 move; a $185 strike lets the stock run $15 before the cap bites. The premium you collect is the price you’re paid for accepting that cap, and a higher cap is worth less, so it pays less.
The strike you choose is just where you set the balance between cash now and room to run. There is no strike that gives you both: more of one is always less of the other.
Reading assignment odds from delta
Section titled “Reading assignment odds from delta”When you’re weighing strikes, you want some sense of how likely each one is to take your shares. The option’s delta, a number the options chain reports for every strike between 0 and 1, is the usual stand-in. A delta near 0.30 is a rough proxy for roughly a 30% chance the option finishes in the money. It is a guide for ranking strikes against each other, not a measurement: delta is built from a pricing model’s assumptions, not a direct readout of assignment probability, so treat it as approximate.
Used that way, delta is handy. The strike closest to the money in the example would carry the highest delta and the highest premium; the far-out strike, the lowest of both. Many sellers writing for income look in the 0.20–0.30 delta range, a rough proxy for a 70–80% chance the option expires without taking their shares, because it collects a usable premium while leaving assignment the less likely outcome. That is a common starting anchor, not a rule, and it still sits behind the willingness-to-sell question: a strike inside your happy-to-sell range at 0.35 delta beats one outside it at 0.20.
The second dial: how expiration moves the same trade-off
Section titled “The second dial: how expiration moves the same trade-off”The strike sets the balance; the expiration date adjusts the same one. It moves two things at once.
A longer-dated call collects more premium. More time means more chances for the stock to reach the strike, so the buyer pays more for it. A 60-day call collects more than a 35-day call at the same strike. But the per-day rate of decay (the part of the premium that erodes in your favor as time passes) is slower far from expiration and faster as the date nears. For why the decay curve steepens, see about time decay.
A longer-dated call exposes you to more events. The more calendar you sell, the more likely an earnings report, an ex-dividend date, or a sharp move falls before expiration. Earnings in particular can swing a stock 10–20% in a day and reprice the option in ways that work against a seller. Before you settle on an expiration, check whether an earnings date lands inside it and decide deliberately whether you want that exposure.
Many income-focused sellers land in the 30–45 day range: long enough to collect a worthwhile premium and capture a good share of the time decay, short enough to limit how many events you’re exposed to and to keep a natural monthly rhythm. Shorter expirations decay faster per day but demand more frequent attention and leave less time to react when a stock gaps. As with the strike, this is a starting point, not a prescription. The right expiration depends on how much premium you need, what’s on the calendar, and how often you want to be managing the position.
When the highest premium is the wrong choice
Section titled “When the highest premium is the wrong choice”The premium column always tempts you toward the closest strike, because that is where the cash is largest. Resist reading the table that way. The strike closest to the price pays most precisely because it is most likely to sell your shares, and at the soonest, smallest gain. If that price isn’t one you’d actually be glad to sell at, the premium is paying you to accept an outcome you don’t want. Pick the strike from the sell price you’d be happy with, then take whatever premium that strike happens to offer.
Where to go next
Section titled “Where to go next”- How covered calls work: the full mechanics of selling a call against shares you own, and the three ways a position can resolve.
- When you get assigned: what happens, and what it costs in upside, when the stock finishes above your strike.
- The Greeks: delta, theta, and the rest of what the options chain reports, and how each one shapes a premium.
- A covered call, start to finish: one worked trade carried from strike choice through to the outcome.