How does caffeine tracking work?

Log a coffee, a tea or an energy drink as you would any food, and Tone tracks the caffeine in it.

Tone shows how much caffeine is still active in your body, using a five-hour half-life, the day’s peak, and the latest time you could have another coffee and still be under 50 mg by bedtime, a level unlikely to get in the way of sleep.

Your daily limit starts at 400 mg, the FDA’s figure for most adults. You can change it in Settings › Daily Caffeine Limit.