Calculators

Caffeine calculators

Interactive tools built on the CoffeeLog engine — half-life, bedtime cutoff, safe limits and side-by-side comparisons.

Metabolism & sleep

Caffeine half-life calculator Add the drinks you had and see how much caffeine is in your system now, at bedtime, and the latest cup you can still have before it touches your sleep.

Last cup before bed Find the latest time you can have a coffee and still fall below the caffeine level that disturbs sleep by your bedtime.

Dose & safety

Safe daily caffeine limit See a personalized safe caffeine ceiling based on body weight, alongside the general FDA 400 mg/day guideline.

Comparison & converters

Compare two drinks Compare the caffeine content of any two drinks and see the difference in mg and cups of coffee.

CoffeeLog · iOS

Track this automatically with CoffeeLog

Log any drink in one tap, watch caffeine fade in real time on your home screen, and get a nudge before it touches your sleep — the same engine that powers this page.

Coming soon