Expected Move: The One Number to Check Before Any Earnings Trade

The expected move is the range the options market is pricing for a stock over a given period. It is the single most useful number to check before any earnings trade, and most people either ignore it or calculate it wrong.

It is not a forecast. It is a statement about what other participants are collectively willing to pay for protection and leverage, converted into a price range. That distinction is what makes it tradeable.

Two Ways to Calculate It

The straddle method is the quick one. Take the at-the-money call price plus the at-the-money put price for the expiration you care about. That sum, roughly, is the expected move in dollars.

If a stock trades at $180 and the $180 straddle costs $9.50, the market is pricing about a $9.50 move by expiration in either direction — a range of $170.50 to $189.50. That is a 5.3% expected move.

A slight refinement multiplies the straddle by about 0.85, because the straddle overstates the one-standard-deviation range somewhat. For most decisions the raw straddle is close enough.

The implied volatility method is more precise and works for any timeframe:

Expected Move = Price × IV × √(Days to Expiration ÷ 365)

That $180 stock at 40% IV with 30 days to expiration gives 180 × 0.40 × √(30/365) = $20.65. This represents roughly one standard deviation, meaning the market prices about a 68% chance of the close landing inside that range.

What the Range Actually Means

One standard deviation covers roughly 68% of outcomes. Two standard deviations — double the expected move — covers about 95%. So a stock priced for a $9.50 move has roughly a one-in-three chance of finishing outside that range, and roughly a one-in-twenty chance of exceeding double it.

This is where the practical value lives. If you are considering a long call with a strike sitting 1.8 expected moves above current price, you are buying something the market assigns a low probability of paying off. That may still be the trade you want, but you should know you are taking it at those odds rather than assuming the strike looked reasonable.

Real stock returns have fatter tails than the normal distribution assumes, so the two-standard- deviation figure understates true tail risk. Gaps happen more often than the math predicts. Treat the numbers as a framework, not a guarantee.

Earnings: The Main Use Case

The expected move is most valuable around earnings, because that is when the options market is pricing a single discrete event rather than a diffuse drift.

Before the print, compare the priced move to the stock's actual historical reaction. If a company has moved an average of 6% on its last eight reports and options are pricing 11%, premium is expensive relative to realized behavior and premium-selling structures — iron condors, strangles — become more attractive. If options price 4% against a 9% history, premium is cheap and long structures make more sense.

This comparison is the entire earnings-options edge in one sentence. Everything else is execution.

After the print, the expected move explains why your direction was right and your position lost. IV collapses the moment uncertainty resolves. A stock that moves 5% when 9% was priced sees extrinsic value evaporate across the whole chain, and a long call can lose money on a green day. This is IV crush, and the expected move is how you see it coming.

Using It for Strike Selection

For premium sellers, the expected move gives a defensible starting point for strikes. Selling a put one expected move below price puts you outside roughly 84% of modeled downside outcomes. Selling at half an expected move roughly doubles your credit and roughly doubles your assignment probability.

For buyers, it sets realistic targets. A long call struck inside the expected move needs an ordinary move to work. One struck well beyond it needs an outlier, and should be sized as a lottery ticket rather than a position.

For spread traders, the range defines where to place short legs. A credit spread with its short strike just outside one expected move and its long strike beyond that has a probability profile you can actually state, rather than a strike chosen because the premium looked appealing.

Where It Misleads

The expected move is symmetric. It says nothing about direction, and equity options are usually skewed — puts trade at higher implied volatility than equidistant calls because downside protection is in structural demand. The true distribution leans lower than the symmetric range implies.

It also assumes volatility stays constant, which it does not. A macro shock mid-cycle expands the range far beyond what was priced at entry, and no static calculation anticipates that.

The options calculator computes expected move for any ticker and expiration alongside the payoff profile, and the earnings calendar pairs upcoming reports with the currently priced move so you can compare it against history before the report rather than after.