Caffeine Half Life Tracker - Free Online Tracker Tool

Quick Answer

The Caffeine Half Life Tracker is a quick tool to monitor how long caffeine stays in your system, with an average half-life of 5 hours (ranging 1.5-9.5 hours).[1][2][3] It helps predict clearance times to avoid sleep disruption—Oura users lost 49 minutes of total sleep on caffeine days—ideal for shift workers, pregnant people, or slow metabolizers (~50% of population).[2][3]

Why You Need a Caffeine Half Life Tracker

Caffeine clearance varies widely due to genetics, age, pregnancy, and more, leading to jitteriness, anxiety, or poor sleep from misjudged timing—like afternoon coffee leaving 50% active by bedtime.[1][2][4] About 90% of U.S. adults consume it daily, but poor tracking worsens issues: caffeine days cut 23 minutes of light sleep and drop Sleep Scores by 8.2 points.[2]

Key stats highlight the need:

• Mean half-life: 5 hours, up to 10+ hours for slow metabolizers (half the population).[1][2][3]
• Pregnancy: Extends to 11-18 hours (average 8.3 hours longer).[2][3]
• Older adults (65+): 33% slower metabolism.[7]
• Oral contraceptives or liver issues: Can double half-life.[1][3]

Shift workers, pregnant individuals (limit <200 mg/day), and late drinkers risk amplified effects—track to plan cutoffs and reclaim rest.[2][4]

How It Works

Enter your caffeine dose (e.g., 95 mg per coffee) and ingestion time—the tracker models exponential decay, showing levels like "50% cleared by 8 PM" or "25% by 1 AM".[1][2][5] It handles multiple doses cumulatively, peaking in 15-60 minutes, for precise predictions.[1][4]

Tips for Best Results

• Input exact doses and times; adjust half-life for factors like pregnancy, smoking, or age (e.g., 4 mg/kg body weight).[1][2][7]
• Aim for <25-50 mg at bedtime to dodge 49+ minutes sleep loss—shift intake mornings for slow metabolizers.[2][4]
• Track cumulatively (coffee + energy drinks); validate with sleep apps and retest as habits change.[1][2]
• Pregnant users: Cap daily totals under guidelines while noting fetal risks.[2][3]

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Sources

• ncbi.nlm.nih.gov
• ouraring.com
• frontiersin.org
• healthline.com
• medicalnewstoday.com