How accurate is this Caffeine Half-Life Calculator?

Our calculator uses scientifically validated formulas and provides results based on peer-reviewed research. Results should be used as a general guide and not as medical advice.

Is this tool free to use?

Yes, this Caffeine Half-Life Calculator is completely free to use. No registration or payment required.

Can I use this calculator on mobile?

Yes, our calculator is fully responsive and works on all devices including smartphones, tablets, and desktop computers.

Caffeine Half-Life Calculator

Calculate how long caffeine stays in your system

Caffeine Half-Life Calculator

Track how long caffeine stays in your system and its impact on sleep

Caffeine Source

Coffee

~95 mg

Espresso

~63 mg

Black Tea

~47 mg

Green Tea

~28 mg

Energy Drink

~80 mg

Cola

~34 mg

Caffeine Pill

~200 mg

Custom

Enter mg

Timing

Time Consumed

Planned Bedtime

Metabolism Factors

Smoking Status

Pregnancy

Regular Caffeine User?

Hours Half-Life

mg at Bedtime

Hours to Clear

Caffeine Levels Over Time

Now +2h +4h +6h +8h +10h +12h

Sleep Impact Assessment

Minimal Sleep Impact

Caffeine should be mostly cleared by bedtime

Recommended: Keep caffeine below 25mg at bedtime for minimal sleep disruption. Even 50mg can increase sleep latency by 20 minutes.

Factors Affecting Caffeine Metabolism

Smoking: Speeds up metabolism by 50%

Pregnancy: Slows metabolism 2-3x

Birth control: Slows metabolism

Genetics: CYP1A2 gene variation

Liver health: Impacts processing

Age: Slower in elderly

Pro Tip: The average half-life of caffeine is 5-6 hours. This means if you drink 200mg at 8 AM, you'll still have 100mg at 1 PM, 50mg at 6 PM, and 25mg at 11 PM. For best sleep, avoid caffeine 8-10 hours before bed.

Caffeine Half-Life

Understand caffeine metabolism.