coffee

Brewed Coffee (240ml / 8oz)

Caffeine Half-Life Analysis

For: Healthy Adult
95
mg Caffeine
5.0
Hour Half-Life
~N/A
Hours to Sleep-Safe
400
mg Daily Limit

trending_down Caffeine Decay Timeline

How 95mg caffeine clears from your system with a 5.0-hour half-life

Time Elapsed Caffeine Remaining % of Original Status
Now (consumption) 95.0 mg
100.0% 		Moderate
After 1 hour 82.7 mg
87.1% 		Moderate
After 2 hours 72.0 mg
75.8% 		Moderate
After 3 hours 62.7 mg
66.0% 		Moderate
After 4 hours 54.6 mg
57.4% 		Moderate
After 5 hours 47.5 mg
50.0% 		Minimal
After 6 hours 41.4 mg
43.5% 		Minimal
After 8 hours 31.3 mg
33.0% 		Minimal
After 10 hours 23.8 mg
25.0% 		Minimal
After 12 hours 18.0 mg
18.9% 		Minimal
After 16 hours 10.3 mg
10.9% 		Minimal
After 20 hours 5.9 mg
6.2% 		Cleared
After 24 hours 3.4 mg
3.6% 		Cleared

health_and_safety Health Insights for Healthy Adult

ℹ️ Health Note

The standard caffeine half-life of 5 hours means that 50% of caffeine is eliminated every 5 hours. After 10 hours, 25% remains; after 15 hours, 12.5% remains.

Daily Limit Calculation

  • • Recommended daily limit: 400mg of caffeine
  • • Caffeine per serving: 95mg
  • • Servings until limit: 4.2 servings

Limit caffeine intake to 400mg/day. Avoid consumption within 6-8 hours of bedtime for optimal sleep.

Sleep Quality Impact

Caffeine blocks adenosine receptors in the brain, preventing the buildup of sleep pressure. Even when you don't feel "wired," residual caffeine can reduce deep sleep quality by up to 20%.

>100mg
May disrupt sleep
50-100mg
Reduced deep sleep
<50mg
Minimal impact

science How Caffeine Half-Life Works

Half-life is the time required for the body to eliminate 50% of a substance. For caffeine, this primarily occurs in the liver through the CYP1A2 enzyme system.

With a half-life of 5.0 hours for healthy adult, caffeine follows exponential decay:

  • After 5.0 hours: 50% remains (47.5mg)
  • After 10.0 hours: 25% remains (23.75mg)
  • After 15.0 hours: 12.5% remains (11.875mg)
  • After 20.0 hours: 6.25% remains (5.9375mg)

The healthy adult category has a average metabolism compared to healthy adults (5 hours baseline). The standard caffeine half-life of 5 hours means that 50% of caffeine is eliminated every 5 hours. After 10 hours, 25% remains; after 15 hours, 12.5% remains.

Compare Other Drinks

Espresso (30ml / 1oz shot) 63mg Red Bull (250ml / 8.4oz) 80mg Monster Energy (473ml / 16oz) 160mg Green Tea (240ml / 8oz) 28mg

Compare Conditions

Smokers 3.0h Pregnancy 10.5h Birth Control Users 7.5h Liver Impairment 12.0h Elderly (65+) 6.5h Fast Metabolizers (Genetic) 3.5h

Related Tools

local_cafe Full Caffeine Calculator hourglass_bottom Caffeine Cut-off Time bedtime Sleep Cycle Calculator

About Brewed Coffee (240ml / 8oz)

Standard drip-brewed coffee

Note: Caffeine can range from 70-140mg depending on brewing method and bean origin

help Frequently Asked Questions

How long does Brewed Coffee (240ml / 8oz) caffeine last for healthy adult?

For healthy adult, the caffeine half-life is approximately 5.0 hours. This means that 95mg of caffeine from Brewed Coffee (240ml / 8oz) will take about 5.0 hours to reduce to 48mg, and 10.0 hours to drop to 24mg. Full clearance (below 10mg) takes approximately 16.2 hours.

When should I stop drinking Brewed Coffee (240ml / 8oz) to sleep well?

If you plan to sleep at 10 PM, you should consume your last Brewed Coffee (240ml / 8oz) by any time - caffeine level is low. This allows approximately sufficient hours for caffeine levels to drop below the sleep disruption threshold of 100mg.

How does being in the 'Healthy Adult' category affect caffeine metabolism?

The standard caffeine half-life of 5 hours means that 50% of caffeine is eliminated every 5 hours. After 10 hours, 25% remains; after 15 hours, 12.5% remains. Limit caffeine intake to 400mg/day. Avoid consumption within 6-8 hours of bedtime for optimal sleep.