Well, it varies so much, I just picked 100mg as a nice round number. However, after a little more research I found this website [http://www.energyfiend.com/the

Well, it varies so much, I just picked 100mg as a nice round number. However, after a little more research I found this website [http://www.energyfiend.com/the-caffeine-database http://www.energyfiend.com/the-caffeine-database] and did an calculation on the average mg per serving and it came out to 109.97, so I think 100mg was a good estimation.