See exactly how option premium erodes day by day as expiry approaches. The silent killer of option buyers — visualize theta decay before you hold overnight.
Current Premium
₹477.72
Value at Expiry
₹0.00
Total Decay (pts)
₹477.72
Total Decay (₹)
₹35,829
per lot (75 shares)
Premium Decay Over Time
Day-wise Decay Snapshot
| Day | DTE | Premium | Theta/day | Decay (₹) |
|---|---|---|---|---|
| 0 | 30 | ₹477.72 | ₹9.09 | ₹682 |
| 7 | 23 | ₹410.94 | ₹10.05 | ₹754 |
| 15 | 15 | ₹323.88 | ₹11.91 | ₹893 |
| 22 | 8 | ₹229.99 | ₹15.48 | ₹1161 |
| 23 | 7 | ₹214.07 | ₹16.39 | ₹1229 |
| 27 | 3 | ₹136.68 | ₹23.87 | ₹1790 |
| 29 | 1 | ₹77.32 | ₹39.74 | ₹2981 |
| 30 | 0 | ₹0.00 | ₹0.00 | ₹0 |
HOW IT WORKS
Input spot, strike, DTE, implied volatility, and risk-free rate.
Select call or put option type.
View a premium decay chart and table showing how much value evaporates each day.
FAQ
Time value decays non-linearly — it decays slowly when there is lots of time, and then rapidly in the final 7-10 days. This is because uncertainty (hence premium) collapses as expiry nears.
Buying options in the last week is very risky due to rapid theta decay. Unless you are expecting an immediate move, the odds strongly favour sellers in the final days.
Yes — options premium typically accounts for weekend decay, meaning Monday open often shows 3 days of theta already priced in (Friday's theta × 3).
Use the current implied volatility from NSE's option chain for the specific strike. For Nifty ATM options, IV typically ranges between 10% and 25%.
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