Caffeine calculator for coffee, tea, cola and energy drinks
The FDA writes "For most adults, the FDA has cited 400 milligrams a day" and describes it "as an amount not generally associated with negative effects" in the FDA consumer update on caffeine, checked October 2, 2026. This caffeine intake calculator adds your day's drinks by type and size against that figure.
| Drink | Serving | Caffeine (mg) | USDA record |
|---|---|---|---|
| Brewed coffee | 8 fl oz | 95 | 171890 |
| Espresso | 1 fl oz shot | 63 | 171891 |
| Black tea | 8 fl oz | 47 | 173227 |
| Green tea | 8 fl oz | 28 | 171917 |
| Cola | 12 fl oz can | 33 | 174852 |
| Energy drink (Red Bull) | 8.4 fl oz can | 75 | 173210 |
Add your drinks for the day
Choose a size and enter a whole number from 0 to 20 for each drink. Leave the count at 0 for any drink you did not have.
Estimated caffeine total
114 mg below the FDA figure
An estimate that varies by brew and brand.
- Brewed coffee, 8 fl oz × 2
- Espresso, 1 fl oz shot × 1
- Cola, 12 fl oz can × 1
FDA figure for most adults
The comparison uses your rounded total so the displayed difference agrees with it.
Two coffees, an espresso and a cola
- Two 8 fl oz cups of brewed coffee, 2 × 237 g × 40 ÷ 100 = 189.6 mg. USDA coffee record.
- One 1 fl oz espresso shot, 29.6 g × 212 ÷ 100 = 62.752 mg. USDA espresso record.
- One 12 fl oz can of cola, 370 g × 9 ÷ 100 = 33.3 mg. USDA cola record.
Total 285.652 mg, shown as 286 mg, which is 114 mg below the FDA figure of 400 mg.
How the numbers are worked out
Milligrams = grams in the serving × caffeine per 100 g ÷ 100. Sizes without their own USDA portion use the record's 1 fl oz weight times the number of fluid ounces.
The six USDA records linked in the table supply the serving weights and caffeine values. The energy drink row is the USDA record for Red Bull, and other energy drink brands differ.
These amounts are estimates that vary by brew, bean, steep time and brand. The full coffee table lists caffeine for more coffee preparations.
People who are pregnant or have a medical condition follow their clinician on caffeine.
Track caffeine with TrueCal Pro
TrueCal Pro tracks caffeine with a daily budget. TrueCal tracks calories and macros on iPhone, Android and the web using sourced nutrition estimates, with free manual calorie logging. Pro includes macros and AI logging from a typed description, voice, a photo or a barcode. This page works out its numbers in your browser and does not save them to the app.
Frequently asked questions
How does this caffeine calculator add up my drinks?
Each serving uses a USDA gram weight and caffeine value per 100 g. The calculator multiplies by the count for each drink, adds the unrounded amounts and rounds the total to whole milligrams.
Where does the 400 mg figure come from?
The figure comes from the FDA consumer update on caffeine and refers to most adults.
Why does my coffee shop drink differ from the table?
Caffeine varies by brew, bean, steep time and brand. These USDA records provide estimates for the listed drinks rather than measurements of your particular drink.
Which energy drink does the calculator use?
The energy drink amounts use the USDA record for Red Bull. Other energy drink brands differ.
Sources
- The FDA consumer update on caffeine, checked October 2, 2026.
- USDA Brewed coffee record 171890, checked October 2, 2026.
- USDA Espresso record 171891, checked October 2, 2026.
- USDA Black tea record 173227, checked October 2, 2026.
- USDA Green tea record 171917, checked October 2, 2026.
- USDA Cola record 174852, checked October 2, 2026.
- USDA Energy drink (Red Bull) record 173210, checked October 2, 2026.
- TrueCal AI info, checked October 2, 2026.
- TrueCal product facts, checked October 2, 2026.
Add drinks by type, serving size and count to estimate caffeine in milligrams beside the FDA figure for most adults.
Related calculators and guides
For a separate calculation based on weight and exercise, open the water intake calculator.