Every options chain contains a hidden forecast. Buried in the premiums is the market's collective bet on how far a stock is likely to move — the expected move. Learn to read it and you'll know whether an options price is cheap or expensive, how much cushion your strikes really have, and just how much fireworks the market expects from an earnings report. It's one of the most useful numbers in options, and most traders never calculate it.
What the expected move actually is
The expected move is the range a stock is projected to stay within over some period — usually quoted as one standard deviation, which covers roughly 68% of outcomes. If a $100 stock has an expected move of ±$6 over the next month, the market is pricing about a two-in-three chance it lands between $94 and $106. It says nothing about direction — only magnitude. A big expected move means the market expects a lot of movement (and options are pricey); a small one means calm (and cheap options).
Two ways to calculate it
1. From implied volatility
Implied volatility (IV) is annualized, so you scale it to your time frame:
Expected move ≈ Stock price × IV × √(days ÷ 365)
A $100 stock at 30% IV over 30 days: 100 × 0.30 × √(30/365) ≈ ±$8.60. That's your one-standard-deviation range for the month.
2. From the ATM straddle
A quicker shortcut: add the price of the at-the-money call and the at-the-money put for your expiration. That straddle price is a close approximation of the expected move to that date. If the ATM call is $4.20 and the ATM put is $4.00, the market's expected move is roughly ±$8.20. The expected move calculator handles both methods; the implied move calculator focuses on the IV approach.
The earnings expected move
Expected move shines around earnings. In the days before a report, traders bid up options because a big surprise is possible, so IV — and the expected move — balloon. The ATM straddle right before the announcement tells you the one-day move the market is pricing in. If a $50 stock's pre-earnings straddle is $4, the market expects roughly a ±$4 (8%) move on the news. That's gold for two reasons: it tells option buyers whether they're paying up for a move that may not materialize, and it tells option sellers (and wheel traders) how far their strikes should sit to survive the report. The earnings expected move calculator gives you that number fast.
How to actually use it
- Sanity-check option prices. If you're buying a move you think is bigger than the expected move, you have an edge on magnitude; if smaller, you're overpaying.
- Place strikes with cushion. Selling cash-secured puts or covered calls? Putting strikes outside the expected move raises your odds of expiring safely (at the cost of less premium).
- Respect the IV crush. After earnings, IV collapses and options lose value fast — a move exactly equal to the expected move can still lose a long-option buyer money. This is why "buy options before earnings" so often disappoints.
The expected move won't tell you which way a stock goes — nothing does — but it tells you what the market has already priced in, which is often more valuable. Run the numbers with the expected move calculator before your next options trade.