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Reference-only calculation
The result uses your inputs and general reference ranges. Real decisions can change with health status, medication, pregnancy or postpartum status, and medical history.
Caffeine half-life calculator
Caffeine half-life calculator. Enter values to calculate a reference result; health decisions should be made with professional guidance.
Inputs
Medical and Safety Note
This tool is for reference only and does not replace medical diagnosis or treatment. Always consult a qualified health professional for diagnosis and care.
Caffeine varies widely by person; this calculator uses a simple 5-hour half-life assumption.
Before You Use It
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How tracker data is stored
Tracker-style tools save only in this browser’s localStorage. Data may disappear if you switch devices, clear browser data, or use private browsing.
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Caffeine half-life varies widely
FDA consumer guidance describes about 400 mg per day as a common upper amount for healthy adults, but sensitivity varies. Pregnancy, liver disease, medications, smoking status, and metabolism can change the remaining amount.
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For sleep, be conservative after midday
CDC sleep habit guidance recommends avoiding caffeine in the afternoon or evening. This calculator is an average model, so use stricter cutoffs if you notice insomnia, palpitations, or anxiety.
Frequently asked questions
Can this diagnose anything?
No. This page is a calculation and logging aid only. It does not replace diagnosis, treatment, or prescribing.
Is my data saved on a server?
No. Tracker features use only this browser’s local storage.