Caffeine Tracker - Half-Life

Coffee at 3 pm, wide awake at midnight. If that sounds familiar, the problem usually isn't how much you drink — it's how much caffeine is still in your body when you go to bed.

This caffeine tracker logs each coffee, tea, or energy drink in one tap and runs it through a half-life decay curve. Instead of a daily total, you see a live estimate of what's in your system right now, and what will be left at bedtime.

• One-tap logging with common drink presets

• A decay chart that shows your level through the day

• A bedtime readout, so you know when your last cup should be

• A daily limit gauge based on the common 400 mg guideline

There is no account to create and no subscription. Everything stays on your phone and works offline.

Made for people who run on coffee but would also like to sleep: office workers, students, shift workers, and anyone cutting back without quitting.

Estimates are based on average caffeine metabolism and are for reference only, not medical advice.