Implied volatility reflects priced uncertainty
Implied volatility is an input derived from option prices. Higher implied volatility generally increases the theoretical value of both calls and puts because wider price movement is being priced into the option.
It is not a directional forecast. An option can lose value after a favorable stock move if implied volatility falls enough.
Time decay accelerates near expiration
All else equal, options lose time value as expiration approaches. This effect is especially relevant for long options that need a move soon and for short options that retain time value until they are closed or expire.
A calendar spread is particularly sensitive because it owns and sells options with different expirations. Its outcome depends on both legs’ time value and implied volatility.
Planning with both inputs
Use a scenario calculator to compare the same target price at different dates and volatility assumptions. For example, a call may be worth less at the same stock price two weeks later if its remaining time value has declined.
Models simplify a live market. Liquidity, bid-ask spreads, dividends, and changing rates can affect observed prices.