Caffeine Calculator: How Much Caffeine Have You Had Today?
An 8 oz cup of brewed coffee has about 95 mg of caffeine, and the FDA cites 400 mg a day as an amount not generally linked to negative effects for most healthy adults. Tap in today's drinks to see your total.
| Drink | Caffeine | How many |
|---|---|---|
| Brewed coffee, 8 fl oz | 95 mg | |
| Brewed coffee, 12 fl oz | 142 mg | |
| Brewed coffee, 16 fl oz | 189 mg | |
| Espresso, single shot (1 fl oz) | 64 mg | |
| Black tea, 8 fl oz | 47 mg | |
| Green tea, 8 fl oz | 28 mg | |
| Cola, 12 fl oz | 32 mg | |
| Red Bull, 8.4 fl oz | 73 mg |
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See Wake Up SmartHow the caffeine calculator works
This caffeine calculator adds up the caffeine from everything you drink in a day and shows how your total compares with the FDA's 400 mg daily reference for most healthy adults. That's about two to three 12 oz cups of brewed coffee.
Drink values come from USDA FoodData Central lab data, scaled to common US serving sizes: brewed coffee is about 40 mg per 100 g (95 mg per 8 oz), espresso 212 mg per 100 g (about 64 mg per shot), black tea 20 mg (47 mg per 8 oz), green tea 12 mg (28 mg per 8 oz) and cola 9 mg (32 mg per 12 oz). Energy drinks vary the most, from about 54 to 328 mg per 16 oz according to the FDA, so add those from the label with the custom field.
Real numbers shift with bean, roast, brew time and cup size. A large coffee-shop cup can hold far more than a home-brewed 8 oz, so read the totals as estimates.
Knowing your daily total is half the picture. The other half is timing: caffeine late in the day is linked to shorter, lighter sleep. Pair this counter with the caffeine cutoff calculator to see when your last cup should be for your bedtime.
How it works
Pick your drinks and we add up the caffeine. Values come from USDA FoodData Central lab data per 100 g, scaled to common US serving sizes (about 1 g per mL).
Brewing method, bean and brand change the real number a lot, so for energy drinks and pre-workouts always use the label.
What the research says
- The FDA cites 400 mg a day, about two to three 12 oz cups of coffee, as an amount not generally associated with negative effects for most healthy adults. Read the study
- FDA: energy drinks range from about 54 to 328 mg of caffeine per 16 fl oz. Read the study
- USDA FoodData Central lists caffeine per 100 g: brewed coffee 40 mg, espresso 212 mg, black tea 20 mg, green tea 12 mg, cola 9 mg. Read the study
Glossary
- mg
- Milligram, one-thousandth of a gram.
- FoodData Central
- USDA's public database of food nutrient values.
- Serving size
- The amount the caffeine number refers to, such as 8 fl oz.
Frequently asked questions
How much caffeine is too much in a day?
The FDA cites 400 mg a day, about two to three 12 oz cups of coffee, as an amount not generally associated with negative effects for most healthy adults. Sensitivity varies widely from person to person.
How much caffeine is in a cup of coffee?
About 95 mg in an 8 oz cup of brewed coffee, based on USDA data. A single 1 oz espresso shot has about 64 mg.
How much caffeine is in tea?
About 47 mg in 8 oz of brewed black tea and about 28 mg in 8 oz of brewed green tea, based on USDA data.
How much caffeine is in an energy drink?
It varies widely. The FDA reports about 54 to 328 mg per 16 oz. An 8.4 oz Red Bull is about 73 mg based on USDA data. Always check the label.
Does decaf coffee have caffeine?
A little. The FDA says decaf coffee typically has 2 to 15 mg of caffeine in an 8 oz cup.
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- USDA FoodData Central, SR Legacy caffeine values per 100 g: brewed coffee 40 mg (FDC 171890), espresso 212 mg (171891), black tea 20 mg (173227), green tea 12 mg (171917), cola 9 mg (174852), Red Bull 29 mg (173210). Serving totals assume about 1 g per mL. https://fdc.nal.usda.gov/
- U.S. FDA. Spilling the Beans: How Much Caffeine Is Too Much? https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
For information only, not medical advice.