Theta decay formula

Plz tell me about theta decay formula, plz tell if nifty 22000 pe Greek theta is 20, what is theta 20 means?

I’m not an expert but in simple terms theta means time decay of option value till expiry. For e.g. If u buy option of 22000CE at a premium of 5000 with 50 lot value, with 7 days of expiry left then in this case assuming theta of 20 means option value loses 20 Rs per day whenever an option value nears it’s expiry.

It is wrong sir, But thnk u, u give ur valuable time to solve my problem

I’m not here for judging anybody whether he is & here I’m not wrong or correct, have provided you with an simple example for your question so that u understand. If u think I’m wrong then correct me with what u understand Theta means.

Thanks for replying, I want to know exect formula, not roughly formula. I don’t know so I posted here. But which was u posted, I have checked it, it is not like this