Sold a put or call? See where your premium should be today and what buy-to-close target to set.
On a linear time-decay schedule, the premium should be around $2.50 today. If you can buy to close at or below this price, you're tracking or ahead of schedule. If the market is asking more, the underlying moved against you or IV expanded — the math isn't the whole story.
Set a GTC buy-to-close order at this price. If filled before the date, you captured half the premium in less than half the time — close and redeploy.
More conservative target. Theta accelerates near expiry — many traders close around 75% to avoid gamma risk on the last 25% of premium.
This calculator handles the easy part — time decay arithmetic. The hard part is picking the right strike, the right expiry, and the right underlying for current market conditions. Top GIOAT options sellers post their trades in real-time, with verified track records you can audit before you follow.
The calculator uses a linear time-decay model: it assumes premium evaporates evenly across the life of the trade. Day 7 of 28 = 25% decay = premium should be at 75% of where you sold it. Simple, conservative, and good enough for setting GTC close orders.
Reality is faster than linear near expiry. Real theta accelerates — the last week of a 30-day option decays much faster than the first week. So if the calculator says you're at 50% decay on schedule, the actual market price is often below that level. Use the linear target as a floor; the real market may give you better fills.
Why 50% and 75%? Standard rules of thumb among options sellers. At 50% you've captured half the premium in (usually) less than half the time — closing locks in the win and frees the capital for the next trade. At 75% you're squeezing more out of the trade but accepting more gamma risk on the remaining premium.
What this can't see. The math ignores three things real traders watch: delta (underlying price moved against you), IV (volatility expanded, making the option more expensive), and gamma (acceleration risk near expiry as the strike approaches). All three can override the schedule. If the underlying has dropped 5% since you sold a put, your "ahead of schedule" decay may be entirely wiped out by delta.