Size My Habit

Coffee & Tea Calculator

How does your daily caffeine intake stack up against health guidelines, or how much volume does your beverage habit displace? Find out now.

Size My Coffee & Tea

Avg. 240mL cup. RDA: Adults ~4 cups, Pregnancy ~2 cups, Adolescents ~1 cup.

Your Habit Scale

Estimated health impact based on your inputs.
AssessmentYour Consumption vs. Guideline
Your Coffee Cups Per Day3
The Coffee Cups RDA per Day4.21
Your Consumption vs. Guideline-28.7%

How It's Calculated

  • 1. Your input: 3 Coffee Cups per day. This is equivalent to an average of 285.0 mg of caffeine per day.
  • 2. The recommended daily allowance (RDA) is 400 mg of caffeine per day.
  • 3. The percentage difference is calculated as: ((Your Daily Intake - RDA) / RDA) × 100%.
  • 4. This helps you see if your consumption is above or below health guidelines.

Why It's Important

This tool directly measures your daily caffeine intake against official health guidelines. The recommended daily allowance (RDA) for adults is 400mg. Based on your input, your consumption is -28.7%% below this guideline.

Why is this important? Staying within these limits helps you enjoy caffeine’s benefits—like improved focus and alertness—without increasing the risk of negative side effects like anxiety, jitteriness, or sleep disruption. For specific groups like pregnant women or adolescents, these limits are based on evidence linking higher caffeine intake to potential health risks. This personalized comparison empowers you to make informed decisions for your health and well-being.

The Science Behind It

Caffeine is the world’s most widely consumed psychoactive substance, prized for its alertness-boosting effects. This calculator helps you compare your daily intake from various sources against established safety guidelines from leading health organizations.

1. How Caffeine Works

Caffeine's primary effect is blocking adenosine receptors in the brain. Adenosine is a neurotransmitter that promotes sleepiness. By inhibiting it, caffeine increases alertness and neuronal activity.

2. Recommended Daily Allowances (RDAs)

The RDAs used in this calculator are based on comprehensive safety assessments from health authorities like the FDA and EFSA.

  • Healthy Adults (400 mg): This limit is associated with no adverse effects in the general population.
  • Pregnant Women (200 mg): Lower limits are recommended to reduce potential risks of pregnancy loss or low birth weight.
  • Adolescents (100 mg): This guideline protects against potential negative effects on sleep and anxiety in younger individuals.

3. Why Do Caffeine Amounts Vary?

The caffeine content in coffee and tea can vary significantly based on the type of bean or leaf, brewing method, and preparation time. Our calculator uses widely accepted averages for common beverages:

  • Coffee (240 mL cup): ~95 mg
  • Espresso (30 mL shot): ~65 mg
  • Black Tea (240 mL cup): ~47 mg
  • Green Tea (240 mL cup): ~29 mg