Theta Θ
How much an option's value decays with one day's passage of time.
Quick Answer
Theta measures how much value an option loses each day purely from the passage of time — the daily 'rent' an option buyer pays and an option seller collects.
Theta is one of the option Greeks — how much an option's value decays with one day's passage of time. OptionsGyan teaches the options fundamentals; the complete reference for Theta — the plain-English meaning, formula, original diagram, a worked Nifty example, common mistakes and FAQ — lives on GreeksGyan, our dedicated option-Greeks site.
Read the full Theta guide on GreeksGyan
Theta (Θ) — the full guide
Meaning, formula, diagram, Nifty worked example, misconceptions and FAQ.
All the option Greeks
Delta, Gamma, Theta, Vega, Rho and the second-order Greeks, in one reference.
Related on OptionsGyan: the Option Greeks overview, the options calculators and the options fundamentals. Or jump straight to Theta on GreeksGyan →
Published 1 July 2026. Educational content only — not investment advice.