What Is the Relationship between an Option’s Premium and Its Implied Volatility (Vega)?

Vega is the option Greek that measures the sensitivity of the option's premium to a 1% change in implied volatility. The relationship is direct and positive: as implied volatility increases, the option premium rises, and vice versa.

This is because higher volatility increases the chance of the option becoming profitable (ITM) before expiration, thus increasing its extrinsic value.