Caffeine Calculator
Track daily caffeine intake from beverages and food against the 400mg recommended limit.
About this tool
The Caffeine Calculator helps you monitor your daily caffeine consumption against the 400 mg guideline recommended by health authorities like the FDA. Caffeine sensitivity varies significantly between individuals—factors like body weight, metabolism, medications, and pregnancy status all influence how your body processes caffeine. This tool lets you track intake from coffee, tea, energy drinks, chocolate, and other common sources to understand your personal caffeine habits and maintain a healthier balance.
To use the calculator, simply select beverages and food items from the list, specify quantities, and the tool instantly tallies your total intake. You'll see whether you're within the recommended limit, and a color-coded indicator (green for safe, yellow for approaching the limit, red for exceeded) provides quick visual feedback. This is useful for anyone managing migraines, anxiety, sleep issues, or simply wanting to be more mindful of stimulant consumption.
Keep in mind that caffeine content varies by brewing method and product brand—a strong espresso differs significantly from a mild latte, and energy drink formulations change frequently. The values in this tool are approximate averages, so use them as a guide rather than absolute measures. If you're pregnant, nursing, taking certain medications, or have caffeine-sensitive conditions, consult your healthcare provider about your individual limit.
Frequently Asked Questions
Code Implementation
def caffeine_remaining(initial_mg: float, elapsed_hours: float, half_life_hours: float = 5.5) -> float:
"""
Calculate remaining caffeine using half-life decay formula.
C(t) = C0 * (0.5)^(t / t½)
Default half-life: 5.5 hours (adult average).
"""
return initial_mg * (0.5 ** (elapsed_hours / half_life_hours))
def hours_until_threshold(initial_mg: float, threshold_mg: float, half_life: float = 5.5) -> float:
"""
Calculate hours until caffeine drops below threshold.
t = t½ * log2(C0 / threshold)
"""
import math
if threshold_mg <= 0 or initial_mg <= threshold_mg:
return 0.0
return half_life * math.log2(initial_mg / threshold_mg)
# Example: Morning coffee at 07:00
initial_mg = 200 # large drip coffee
half_life = 5.5
print("Caffeine decay after a 200 mg coffee:")
print(f"{'Time':>8} {'Remaining (mg)':>16} {'% Left':>8}")
print("-" * 38)
for h in range(0, 14):
remaining = caffeine_remaining(initial_mg, h, half_life)
pct = remaining / initial_mg * 100
print(f"{h:>7}h {remaining:>14.1f} {pct:>7.1f}%")
# Bedtime estimate
bedtime_h = hours_until_threshold(initial_mg, 25) # <25 mg feels negligible
print(f"\nTime until <25 mg remains: {bedtime_h:.1f} hours after intake")Comments & Feedback
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