What calculation do i need to work out how much price will drop if i dump my coins?

I know there is market cap eg 500k, number of tokens eg 100 million, price eg 0.0002, tokens held eg 1 million.

I want to know if there is a calculation i can use to determine what price will be if i dump my 1 million tokens at the current market cap, at the current price, and how much would i get for the tokens, becasue i believe that if i had 1 million to sell, by the time i sold 1000 the price would have changed…

I want to know all this for a program i want to write in python to work all this out.

thanks..