The amount of grout needed for a job depends on the size of the job (in square feet), the size of the tile, and its thickness.
Since we only work with Bostik Grouts, you may use their Online Grout Calculator here https://www.bostik.com/us/tools-and-training/grout-calculator/ to calculate the amount you need. Make sure to select either the Diamond RapidCure or TrueColor RapidCure", which are the two grout lines we offer at https://www.mineraltiles.com