What Is Vega in Options? How Implied Volatility Moves Option Prices
Reviewed by Leon Moyer - Published October 9, 2026 - Last reviewed October 9, 2026
In this lesson
Use vega to estimate how an option's price will change when implied volatility rises or falls, and explain which options carry the most vega.
Vega is the amount an option's price is expected to change for a 1 percentage point change in implied volatility, with everything else held constant. Long calls and long puts both have positive vega: they gain value when implied volatility rises and lose value when it falls.
Vega is the Greek that most often surprises new traders, because it can move an option's price while the stock sits still. This lesson uses the module's standard inputs: XYZ at $50, the XYZ 50 call with 30 days left, 30% implied volatility and a 4.5% interest rate.
What is implied volatility?
Implied volatility (IV) is the size of the stock's future moves that the market is pricing into its options, stated as an annualized percentage. When traders expect big moves, such as ahead of an earnings report, they pay more for options, and implied volatility rises. When things calm down, it falls. What Is Implied Volatility? covers where implied volatility comes from, and IV Rank and IV Percentile covers how to judge whether it is high or low. For this lesson, all you need is that it goes up and down, and vega tells you what that does to an option's price.
How does vega work in options?
In one sentence: estimated change in an option's price = vega x the change in implied volatility, in percentage points.
The XYZ 50 call's vega is about $0.057 per share, or $5.70 per contract. If implied volatility rises from 30% to 31%, the call gains about $5.70; if it falls to 29%, the call loses about $5.70.
Vega: the same call at five levels of implied volatility
Value per contract at each implied volatility
For this at-the-money example, that relationship is close to a straight line. With XYZ at $50 and 30 days left, the call is worth $124 per contract at 20% implied volatility, $181 at 30% and $238 at 40%. Each 5-point step moves it about $28.50, which is 5 x $5.70.
Vega is positive for puts as well. The XYZ 50 put's vega is also $5.70 per contract, because more expected movement makes the right to sell more valuable too. Sellers have the opposite sign: someone who sold the 50 call has a vega of -$5.70 and gains when implied volatility falls.
See OIC on vega.
How much does a drop in implied volatility cost?
The same vega rule works for falls. When implied volatility drops, every long option loses value, and longer-dated options lose more dollars because they have more vega. A sharp drop after an expected event such as an earnings report is called IV crush; IV Crush After Earnings, in the next module, works through what it does to a trade.
Worked example
A 5-point drop in implied volatility at three expirations
XYZ trades at $50 and stays there. Implied volatility on its 50 calls falls from 30% to 25%, and nothing else changes. Here is each call's model value per contract before and after, next to the loss its vega predicts (5 x vega):
- In dollars, the 90-day call loses more than three times as much as the 7-day call, because its vega is $9.80 per contract against $2.76.
- As a share of the premium, the losses are similar: about 15% for the 90-day call and about 16% for the 7-day call.
- For a near-the-money option like this one, vega x the change in points predicts the loss almost exactly. For bigger IV changes, or options far from the money, treat it as an estimate.
Illustrative and hypothetical. The ticker and prices are invented for teaching, and the figures exclude commissions, fees, margin interest and taxes, which reduce real results. Past or hypothetical outcomes do not indicate future results.
Vega: what a 5-point drop in implied volatility costs
Loss per contract from a 5-point IV drop
A spread that sells one option against another can offset part of the vega; the Building a Strategy course covers those structures.
Which options have the highest vega?
Vega is generally largest near the money and is usually larger for longer-dated options with otherwise comparable inputs, because a longer-dated option has more time for volatility to matter. For the XYZ 50 call with XYZ at $50:
Out-of-the-money options have less vega in dollars: the XYZ 55 call's vega with 30 days left is $3.39 per contract. As a share of a small premium, though, a change in implied volatility can still move them a long way.
Notice how this is the reverse of gamma and theta. Short-dated at-the-money options have the most gamma and theta, while long-dated ones have the most vega. For equal contract counts in this example, a 90-day option has more dollar sensitivity to a one-point IV change than a 7-day option. That does not mean a larger percentage sensitivity or that both expirations experience the same IV change.
How do the four Greeks fit together?
With vega, you now have all four Greeks that move prices day to day. For the at-the-money examples here, the four basic positions from Buyers and Sellers have these signs. Theta signs can differ for other inputs, as What Is Theta in Options? explains:
A call buyer benefits from a rise in the stock; a put buyer benefits from a fall. Both benefit from rising IV with other inputs fixed, and usually face time decay. Sellers take the opposite exposures. Every strategy in later courses is a way of choosing which of these exposures to hold. The next module, starting with Intrinsic and Extrinsic Value, goes deeper into implied volatility and how it sets option prices in the first place.
A short call you do not cover with shares has unlimited risk: its loss grows with every dollar the stock rises above the strike. A short put can lose up to the strike x 100 minus the premium.
Check your understanding
An option has a vega of $0.08 per share. Roughly how much does one contract change if implied volatility falls 5 points?
Show answer
It loses about $40: vega per share x 100 x the change in points, $0.08 x 100 x 5.
Does a long put gain or lose when implied volatility rises, if the stock does not move?
Show answer
It gains. Long puts, like long calls, have positive vega, because higher expected movement makes the option more valuable.
With XYZ at $50, implied volatility on its 50 calls falls 5 points and the stock does not move. Which loses more dollars per contract, the 90-day call or the 7-day call, and roughly how much?
Show answer
The 90-day call. Its vega is $9.80 per contract, so it loses about 5 x $9.80 = $49; the 7-day call's vega is $2.76, so it loses about $13.80. As a share of each premium, the losses are similar.
Key takeaways
- Vega estimates how much an option's price changes for a 1 point change in implied volatility; the example call's vega is $5.70 per contract.
- Long calls and long puts both have positive vega; sellers have negative vega.
- A drop in implied volatility costs a long option about vega x the points lost; longer-dated options lose more dollars for the same drop.
- Vega is generally highest near the money and larger for longer-dated options with comparable inputs.
Common questions
What does a vega of 0.10 mean?
The option's price is expected to rise about $0.10 per share, or $10 per contract, for each 1 percentage point rise in implied volatility, and to fall by the same amount for each 1 point drop, with everything else unchanged.
Do puts have positive vega?
Yes. Higher implied volatility makes both calls and puts more valuable, so long calls and long puts both have positive vega. Sellers of either have negative vega and benefit when implied volatility falls.
Is vega the same as implied volatility?
No. Implied volatility is the size of future moves the market is pricing into an option, stated as an annualized percentage. Vega is the option's sensitivity to that number: how many dollars its price changes for each 1 point change in implied volatility.
Which options have the highest vega?
At-the-money options with a lot of time left. In this lesson's example, the at-the-money call's vega is $9.80 per contract with 90 days left, $5.70 with 30 days left and $2.76 with 7 days left.