If I recall correctly, this will get you a standard deviation of 1. let result = 0; for (let i = 0; i < 6; i++) { result += Math.random() - Math.random

If I recall correctly, this will get you a standard deviation of 1. let result = 0; for (let i = 0; i < 6; i++) { result += Math.random() - Math.random(); } return result; Obviously this costs 12x as much as Math.random() itself, but it sure is simple. (It'll also never return anything more than 6 standard deviations away from the mean, but it's not like you actually want that in most applications.)