Caffeine Tracker
How much caffeine is left in you
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About this tool
Caffeine leaves the body gradually with an average half-life of about 5 hours. This calculator adds up everything you have had today by drink type, compares the total against the general adult daily limit of 400mg, and estimates how much will still be in your system by the time you plan to sleep. Caffeine shows up not just in coffee but in cola, green tea, and energy drinks too, so mixing drinks can add up faster than expected.
How to use
- Pick the drinks you had today and adjust the count for each.
- Compare your total caffeine intake against the 400mg reference line.
- Enter your planned bedtime.
- Check how much caffeine is estimated to remain at bedtime, and the warning if it may make falling asleep harder.
Frequently asked questions
- Is a 5-hour caffeine half-life accurate?
- 5 hours is an average for healthy adults. In practice it can range from 2 to 10 hours depending on genetics, liver function, pregnancy, and smoking status, so treat the remaining-amount estimate as a general approximation.
- Where does the 400mg daily limit come from?
- It reflects the general upper limit cited by health authorities such as the FDA for healthy adults. People with heart conditions or anxiety disorders may want to stay well below that.
- Does the same 400mg limit apply during pregnancy?
- No. Caffeine metabolism slows during pregnancy, and the commonly recommended limit drops to around 200mg a day. This calculator uses the general adult limit, so pregnant users should apply a lower threshold themselves.
- Does this cover drinks besides coffee?
- Yes. Along with americano, espresso, cold brew, and mix coffee, it also includes energy drinks, cola, and green tea. Combining several of these in one day can push your total up faster than you might expect.
The half-life and remaining amount are average estimates โ actual metabolism varies by person. If you are sensitive to caffeine or take medication that interacts with it, consult a healthcare professional.