FREE · HEALTH & FITNESS CALCULATORS
Caffeine Calculator.
Add up the caffeine in your coffee, tea, energy drinks and colas, compare it with the daily guideline and see how much is still in your body at bedtime.
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How to use Caffeine Calculator
Add each drink with the time you had it, set your bedtime and choose the right daily limit. Use “Other” to enter any amount in mg.
How it works
Each dose decays exponentially with a half-life of about 5 hours (adjustable). Limits follow EFSA and FDA guidance: 400 mg a day for adults, 200 mg when pregnant, 3 mg per kg for teenagers.
Example
A coffee at 7:30, a double espresso at 13:00 and a cola at 16:00 add up to 255 mg; about 55 mg is still in your body at 23:00.
Questions about Caffeine Calculator
Is Caffeine Calculator free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
Caffeine content varies by brand and brewing; general information, not medical advice. Everything is calculated in your browser; nothing you type is uploaded. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.