Calculator

Theta Decay Calculator

Estimate the effect of theta on an options position over a selected number of days. Enter the theta value as a daily per-share figure, such as -0.04.

Option price Current option price per share. Daily theta Use the theta value from your platform. Long options commonly show negative theta. Days held Number of calendar days to project. Contracts Contract multiplier Standard U.S. equity options typically use 100. Position type Daily theta adjustment % Optional simple adjustment. Use 0 for constant theta.

Estimated result

This output applies the theta estimate over the holding period and converts the impact into contract-dollar terms.

Initial position value

$0.00

Estimated ending value

$0.00

Estimated time decay

$0.00

Estimated position impact

$0.00

Projected value by day

Projection table

Day	Daily theta	Estimated option price	Estimated position value

Important limitation: This calculator does not price options using Black-Scholes or any other full pricing model. It isolates theta as a simplified estimate. Actual option prices can change because of underlying price movement, implied volatility, dividends, interest rates, bid-ask spreads, early assignment risk, and market liquidity.