What is the formula used to calculate the margin for options?

For Futures we can use Normal Margin Rate to calculate the margin required. I want to know what is the method used to calculate ITM or OTM options margin.

What is the formula used to calculate the margin for options?

For Futures we can use Normal Margin Rate to calculate the margin required. I want to know what is the method used to calculate ITM or OTM options margin.