📖 Overview
Use this tool to track your daily caffeine intake and stay within safe limits.
🧪 Example Scenarios
Use these default and higher-pressure example inputs to explore how sensitive this calculator is before using your real numbers.
| Input | Base Case | Higher Pressure Case |
|---|---|---|
| Number of Drinks | 0 | 0 |
| Caffeine Per Drink (mg) | 2 | 2.3 |
⚙️ How It Works
Multiplies number of drinks by caffeine per drink to get total intake, then compares it to the 400 mg daily upper limit recommended by health authorities for healthy adults.
The Formula
Total Caffeine (mg) = Drinks × Caffeine per Drink (mg)
| Drinks | Number of caffeinated servings consumed |
| Caffeine/Drink | Milligrams of caffeine per serving |
| 400 mg | FDA/EFSA recommended maximum daily caffeine for healthy adults |
💡This calculator is scenario-based. Better input quality leads to better decision quality.
⚠️Pregnant individuals should limit caffeine to ≤200 mg/day. Caffeine sensitivity varies widely — some people experience anxiety or sleep disruption at 200 mg.
Quick Reference
| Drink | Serving size | Caffeine (mg) |
|---|---|---|
| Drip coffee | 8 oz (240 ml) | ~95 |
| Espresso | 1 shot (30 ml) | ~63 |
| Americano | 8 oz | ~95 |
| Black tea | 8 oz | ~47 |
| Green tea | 8 oz | ~28 |
| Energy drink (Red Bull) | 8.4 oz | ~80 |
| Cola (Coke) | 12 oz | ~34 |
When To Use This
- Use this tool when you need a fast decision during active planning or execution.
- Use this before committing money, time, or tradeoffs that are hard to reverse.
- Use this to compare options using the same assumptions across scenarios.
Edge Cases To Watch
- Results can be misleading if key inputs are missing, stale, or unrealistic.
- Very small or very large values may amplify rounding effects and interpretation risk.
- If assumptions change mid-decision, recalculate before acting.
Practical Tips
💡 Track all caffeine sources, including tea, cola, chocolate, and pre-workout supplements.
💡 Caffeine has a half-life of ~5 hours — a 3 pm coffee still has half its caffeine at 8 pm.
💡 Tolerance builds with regular use; sudden cessation can cause withdrawal headaches.
Frequently Asked Questions
❓ Is 400 mg a safe daily limit for everyone?
It is the general guideline for healthy adults. Pregnant people, those with anxiety disorders, or heart conditions should consume less.
❓ Does decaf coffee have any caffeine?
Yes — typically 2–15 mg per cup, not zero.