How Much Caffeine Is in a Cup of Coffee?
By Coffee Ratio Calculator Guru · Updated January 2025 · 5 min read
An average 8oz (237ml) cup of drip coffee contains approximately 95mg of caffeine. Use our caffeine calculator to estimate your intake by brew method, serving size, and number of cups. The actual amount varies significantly by brew method, grind, dose, and coffee origin.
Caffeine by Brew Method
| Brew Method | Caffeine (8oz) | Notes |
|---|---|---|
| Cold Brew (RTD) | ~155mg | High due to concentrated ratio |
| French Press | ~107mg | Full immersion, metal filter |
| Pour Over | ~100mg | Clean extraction, comparable to drip |
| Drip / Auto | ~95mg | Standard reference point |
| Espresso (double, 2oz) | ~126mg | High concentration, small volume |
| Instant Coffee | ~57mg | Lower extraction efficiency |
| Decaf | ~3–5mg | Not caffeine-free |
Does Roast Level Affect Caffeine?
Light roasts contain marginally more caffeine by mass than dark roasts because roasting degrades a small amount of caffeine. However, the difference is typically 5–10% and is easily swamped by differences in dose size, grind, and brew method. The most impactful variable for total caffeine intake is not roast level but brew method and serving size. A 12oz cold brew contains nearly twice the caffeine of an 8oz drip coffee regardless of roast.
The FDA's 400mg Daily Guideline
The FDA considers 400mg of caffeine per day safe for healthy, non-pregnant adults. This corresponds to roughly 4 standard drip coffees or 3 double espressos. Pregnant women are advised to limit to under 200mg/day. Individual sensitivity varies enormously — some people feel jittery at 100mg while others are unaffected at 400mg. Caffeine has a 5–6 hour half-life, so a 200mg coffee at 2pm still has 100mg active at 7pm.
- An 8oz drip coffee has approximately 95mg of caffeine; cold brew RTD has about 155mg.
- Espresso has more caffeine per ml but not necessarily per serving compared to drip coffee.
- Light roasts have slightly more caffeine than dark by mass, but the difference is minor.
- FDA recommends under 400mg/day for healthy adults — about 4 standard cups of drip coffee.
Calculate Your Perfect Ratio
Use our free caffeine calculator to get the exact numbers for your brew method, strength, and cup size — no guesswork required.
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