Estimate an underlying-price move from annualized IV, use an ATM-straddle pricing heuristic, or reverse-solve IV. Day-count conventions and the meaning of each range are shown explicitly.

Educational range estimates, not a forecast or trading recommendation. Use one currency per share throughout. Match the day count to the IV annualization convention.

Enter calendar days for365 or trading days for252. Changing the convention does not convert the entered time.

Options Expected Move Formula

This approximation estimates a move in the underlying price from annualized implied volatility. It does not calculate an option premium or predict direction.

EM = S × IV × √(T / B)

Variables:

  • EM is the approximate absolute underlying-price move in currency per share
  • S is the current price of the underlying asset
  • IV is annualized implied volatility as a decimal (20% = 0.20)
  • T is time until expiration; B is the matching annualization basis:365 calendar days or252 trading days

Multiply spot by decimal IV and by the square root of the matching year fraction. The reverse calculation is IV = EM ÷ S ÷ √(T/B). A straddle-based move instead uses the ATM call-plus-put premium times the selected multiplier. The100% and85% choices are heuristics; neither makes the straddle range a sigma confidence interval.

What is an Options Expected Move?

An IV-based expected move is a simplified, symmetric measure of price variation. The one- and two-sigma labels assume a suitable constant-volatility model, not guaranteed real-world coverage. Jumps, skew and changing volatility can make actual outcomes differ. This is educational information, not a trading recommendation.

How to Calculate Options Expected Move?

The following steps outline how to calculate the Options Expected Move using the given formula:

  1. First, determine the current price of the underlying asset (S).
  2. Next, determine the implied volatility of the option (IV).
  3. Next, determine the time until expiration in days (T).
  4. Use EM = S × IV × √(T/B), matching days to the selected calendar or trading-day convention.
  5. Finally, calculate the Options Expected Move (EM).
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge:

Current price of the underlying asset (S) = $50

Implied volatility of the option (IV) = 0.2

Time until expiration (T) =90 calendar days, B =365. With S =$50 and IV =0.20 (enter20%), EM ≈$4.9656, or9.9313%. The simple1× band is approximately$45.0344 to$54.9656.