What Is Expected Move in Options Trading?

Expected move is the market's own estimate of how far an asset travels by a given date — priced in dollars, and readable straight off the options board.

The formula

The standard approximation is: expected move = price × implied volatility × √(days ÷ 365).

Implied volatility is annualised, so the square-root term rescales it to the horizon you care about. The result is a one standard deviation range, which under normal assumptions contains roughly 68% of outcomes.

A worked example

Take a stock at $200 with 30% implied volatility, and a 30-day horizon. The time factor is √(30 ÷ 365) ≈ 0.287. The expected move is 200 × 0.30 × 0.287 ≈ $17.20.

So the market is pricing roughly a 68% chance the stock finishes between about $183 and $217 in 30 days. Doubling the range to two standard deviations, about $166 to $234, captures roughly 95% of outcomes.

The straddle shortcut

You can skip the formula entirely. The price of the at-the-money straddle — buying both the call and the put at the current strike — is itself a close approximation of the expected move, because that is exactly what the straddle pays for.

If the at-the-money call costs $8.60 and the put costs $8.60, the straddle is $17.20 and the market is pricing about a $17.20 move by expiry. Many traders prefer this because it reads the market's number directly rather than reconstructing it.

What expected move does not tell you

It has no direction. The number is symmetric by construction. It says how far, never which way.

It is a terminal estimate. It describes where the price might finish, not the path. The asset can travel well beyond the expected move and return before expiry.

It inherits the risk premium. Because implied volatility usually exceeds subsequently realized volatility, expected move tends to run slightly wide. Actual moves land inside it more often than the maths suggests.

It assumes a normal-ish distribution. Real returns have fatter tails, so genuinely extreme outcomes are more likely than the two standard deviation band implies.

Where it is most useful

Around known catalysts. Comparing the expected move before earnings against how much the stock has actually moved after previous reports is one of the cleanest ways to judge whether options are expensive or cheap into an event.