I wrote this calculator in JavaScript to help figure out how many mushrooms to eat to reach the desired
trip strength. I don't have a secret unifying formula; I don't think one exists for mushrooms. I did, though,
tweak a formula until it seemed accurate, and then I plugged in variables. I also left it open to user modification, so
you can play with the values so it's customized to your unique reaction to the mushrooms.

Here's a rundown of what all the input fields are for; you probably won't need to modify most of them.