Tallywell.

Caffeine Timeline

The cutoff calculator assumes one drink. Real days have three. Log everything and see the combined curve — plus the one drink worth cutting.

Today's drinks
Your metabolism

Caffeine left at bedtime

DrinkTimeDoseLeft at bedtime

How it's computed

Each drink ramps to peak over ~45 minutes (absorption), then decays with your half-life. The curve is the sum of all drinks. "Cut this one" names the drink whose removal brings your bedtime level under the limit — usually the afternoon one, not the morning one.

One number instead? Cutoff calculator · Why half-lives differ