Caffeine Intake Calculator
Check your daily caffeine intake against safe limits based on body weight.
A typical 8 oz (240 ml) cup of brewed coffee contains about 95 mg of caffeine.
Your Safe Daily Limit
Percentage of Limit
Understanding Your Caffeine Limit
Caffeine is the most widely consumed psychoactive substance in the world, found in coffee, tea, energy drinks, soft drinks, chocolate and some medications. In moderate amounts it can improve alertness and concentration, but excessive intake can cause restlessness, anxiety, a rapid heartbeat, digestive upset and disrupted sleep. The amount that is considered safe depends partly on your body weight, which is why this calculator scales the recommended ceiling to you.
Typical Caffeine Content of Common Drinks
| Source | Approx. Caffeine |
|---|---|
| Brewed coffee (8 oz / 240 ml) | 95 mg |
| Espresso (1 shot) | 63 mg |
| Black tea (8 oz / 240 ml) | 47 mg |
| Cola (12 oz / 355 ml) | 34 mg |
| Energy drink (8 oz / 240 ml) | 80 mg |
How the Limit Is Calculated
The Formula
Health authorities suggest that up to 400 mg of caffeine per day is safe for most healthy adults. Body-weight guidance suggests roughly 6 mg per kilogram per day. This calculator uses the lower (more conservative) of the two figures as your safe daily limit.
Safe daily limit (mg) = min(400, 6 × weight in kg)
Percent of limit = intake / safe daily limit × 100
What the Percentage Means
Your daily intake is expressed as a percentage of your personal safe limit. A value at or below 100% means your intake is within the recommended ceiling, while a value above 100% means you are exceeding it and may benefit from cutting back.
Limitations
This calculator gives a general guideline only. Individual tolerance to caffeine varies widely:
- Sensitivity differs between people. Genetics, regular consumption and metabolism all affect how caffeine impacts you.
- Some groups need lower limits. Pregnant and breastfeeding people are usually advised to stay below 200 mg per day, and limits for children and adolescents are much lower.
- Timing matters. Caffeine consumed late in the day can disrupt sleep even when total intake is within the limit.
- Medications and conditions interact. Heart conditions, anxiety disorders and certain medications may require avoiding caffeine altogether.
References
The limits used in this calculator are based on guidance from food safety and health authorities:
- U.S. Food and Drug Administration (FDA). "Spilling the Beans: How Much Caffeine is Too Much?" FDA Caffeine Guidance
- European Food Safety Authority (EFSA). "Scientific Opinion on the Safety of Caffeine." EFSA Caffeine Opinion
- Mayo Clinic. "Caffeine: How much is too much?" Mayo Clinic Caffeine
Note: This calculator is intended for healthy adults and is for informational purposes only. It does not replace professional medical advice. If you are pregnant, breastfeeding, have a medical condition or take medication, consult a healthcare professional about your caffeine intake.