You bought one TSLA $420 call. Press play and watch 60 days melt away while the stock stays flat, and watch the call lose money anyway. That is theta. Hit the IV spike to see volatility fight back. Drag the time handle on the chart to scrub, and lock any variable to isolate one effect.
The option's value as time runs out
At expiration Value today Strike $420
60days to expiration
Option value
$0
per share
Buyer P / L
$0
per share
Theta / day
$0
value lost per day
Implied vol
45%
entry IV
Plain English
Three things to know about time decay:
Decay accelerates near the end. In practice it is slow far out and speeds up hard in the final weeks.
Watch the IV crush. Volatility tends to fall right after the news, so generally speaking, buying into an event can burn you even when you call the direction.
Buy more time than you think you need. A short-dated option needs you to be right fast, and being right slowly still counts.
Taxes are not shown here. Options and the underlying stock are taxed differently, and it depends on your holding period and account type. None of this is tax advice.