Most people have no idea how much caffeine they actually drink — a morning coffee, a midday soda, and a pre-workout scoop can quietly add up to more than the daily limit before dinner. Enter every caffeinated drink you had today, pick your group, and this calculator totals the milligrams and compares them with the official limits: 400 mg per day for healthy adults, 200 mg per day during pregnancy, and 100 mg per day for teenagers. If you want to know when to stop drinking it so it does not ruin your sleep, our caffeine cutoff calculator works that out from your bedtime.
A "cup of coffee" can mean anything from 63 mg in a single espresso shot to 190 mg in a large 16 fl oz brewed coffee, so counting cups tells you almost nothing. The calculator below adds up the actual milligrams from each drink — brewed coffee 95 mg per 8 fl oz, black tea 47 mg, cola 34 mg per 12 fl oz can, energy drinks 80 mg per 8.4 fl oz can — and shows your total as a percentage of your limit. Use it for your exact drinks.
For healthy adults, the US Food and Drug Administration (FDA) cites 400 mg of caffeine per day as an amount not generally associated with dangerous, negative effects — roughly four 8 fl oz cups of brewed coffee, or about two to three 12 fl oz mugs. The European Food Safety Authority (EFSA) agrees on the 400 mg daily total and adds a single-dose guide: a single dose of up to 200 mg, about 3 mg per kilogram of bodyweight, is not a safety concern for healthy adults. For a 180 lb (about 82 kg) adult, 3 mg per kg works out to about 245 mg in one sitting, which is why the calculator shows a bodyweight-based single-dose guide alongside your daily total. During pregnancy, the American College of Obstetricians and Gynecologists (ACOG) advises keeping caffeine under 200 mg per day, because caffeine crosses the placenta and the fetus clears it slowly. For teenagers ages 12–18, the American Academy of Child and Adolescent Psychiatry caps intake at 100 mg per day, and the American Academy of Pediatrics discourages caffeine and energy drinks for children and adolescents altogether. The FDA has set no safe level for children under 12. These are general-information ceilings, not personal targets and not medical advice — nobody needs 400 mg, and people with anxiety, heart conditions, or sleep problems often feel better well below it.
| Group | Daily limit | Source |
|---|---|---|
| Healthy adults | 400 mg | FDA; EFSA |
| Healthy adults, single dose | 200 mg (about 3 mg/kg bodyweight) | EFSA 2015 opinion |
| Pregnant | Under 200 mg | ACOG; EFSA |
| Teenagers, ages 12–18 | 100 mg | American Academy of Child and Adolescent Psychiatry |
| Children under 12 | No safe level established | FDA; American Academy of Pediatrics |
Caffeine content varies far more than most drinkers expect, and the label is not always helpful — US labeling does not require caffeine amounts on most drinks. The standard values this calculator uses come from the FDA's published caffeine figures: brewed coffee averages 95 mg per 8 fl oz but can range from about 70 to 140 mg depending on bean, roast, and brew strength; a single espresso shot is about 63 mg per 1 fl oz, so a double-shot latte carries about 126 mg before you count anything else; black tea averages 47 mg per 8 fl oz and green tea about 28 mg; a 12 fl oz cola has about 34 mg; and a standard 8.4 fl oz energy drink has about 80 mg, though 16 fl oz energy drinks commonly carry 160 mg and some carry 200 mg or more. Pre-workout is the wildest category: most scoops land between 150 and 300 mg, and this calculator uses 200 mg as a typical value — if your tub says 300 mg, your real total is higher than the calculator shows, so always check the label. Chocolate counts too, though it is small: a 1 oz milk chocolate bar has about 6 mg and a dark chocolate bar about 20 mg, so chocolate rarely moves the total unless you eat a lot of it. The FDA's caffeine guidance is published at FDA: Spilling the Beans — How Much Caffeine is Too Much?, and EFSA's opinion is summarized at EFSA: Caffeine opinion.
| Drink (one serving) | Caffeine | Note |
|---|---|---|
| Brewed coffee, 8 fl oz | 95 mg | Range roughly 70–140 mg by brew |
| Espresso, 1 fl oz shot | 63 mg | Double shot = about 126 mg |
| Black tea, 8 fl oz | 47 mg | Steep time pushes it up or down |
| Green tea, 8 fl oz | 28 mg | Lower than black tea |
| Cola, 12 fl oz can | 34 mg | Diet and regular are similar |
| Energy drink, 8.4 fl oz can | 80 mg | 16 fl oz cans often 160 mg+ |
| Pre-workout, 1 scoop | 200 mg (typical) | Label range about 150–300 mg |
Example 1 — A normal coffee day, under the limit. An adult weighing 180 lbs (about 82 kg) drinks 2 cups of brewed coffee and 1 energy drink: 2 × 95 = 190 mg, plus 80 mg = 270 mg. Against the 400 mg adult limit, that is 270 ÷ 400 = 67.5% of the limit, with 130 mg to spare — roughly one more 8 fl oz coffee. The bodyweight single-dose guide is 82 kg × 3 mg = about 245 mg, and no single drink here comes close to it, so the day is comfortable on both measures.
Example 2 — A pregnancy day that quietly goes over. A pregnant woman drinks one large 16 fl oz brewed coffee — that is two 8 fl oz servings, so 2 × 95 = 190 mg — plus one cup of black tea at 47 mg: 190 + 47 = 237 mg. Against the 200 mg pregnancy limit, that is 237 − 200 = 37 mg over. The trap is the mug size: a "one coffee" day became a two-serving day because the mug held 16 fl oz, and the tea on top pushed it past the line.
Example 3 — A teenager, over on two drinks. A teenager weighing 130 lbs (about 59 kg) drinks 1 energy drink (80 mg) and 1 cola (34 mg): 80 + 34 = 114 mg. Against the 100 mg teen guidance, that is 114 − 100 = 14 mg over — a single energy drink plus a single soda is already past the guidance for ages 12–18, before any coffee or chocolate. That is why pediatric guidance singles out energy drinks: one can alone is 80% of a teenager's whole day.
If your total is under your limit, the useful number is the remainder: it tells you how much room is left for an afternoon drink without crossing the line. If you are over, do not try to fix it by quitting cold turkey tomorrow — caffeine withdrawal headaches are real, and a sudden stop after heavy daily use commonly brings a headache, fatigue, and irritability for 2 to 9 days. Cut back gradually instead: drop one serving, or swap one coffee for a half-caf or a tea, and hold the new level for a few days before cutting again. Timing matters as much as total: caffeine's half-life is about 5 to 6 hours in healthy adults, so half of a 2:00 PM coffee is still in your system at 7:00 or 8:00 PM, and a quarter is still there near midnight — which is why the total and the clock both matter. Our caffeine cutoff calculator turns your bedtime into a last-coffee time. And if your result is high mainly because of pre-workout, check the label first: a scoop that says 300 mg instead of the typical 200 mg changes the whole day's math, and stacking pre-workout on top of morning coffee is the most common way regular gym-goers blow past 400 mg without realizing it.
Written by the Live Fitness Check editorial team · Reviewed against our calculator methodology · Last updated November 2026
Disclaimer: This calculator is for general information only and is not medical advice. Caffeine limits vary by individual, medication, and health condition; the figures here are population guidance from the FDA, EFSA, and ACOG, not a personal recommendation. Talk to your doctor if you are pregnant, take medication, or have a heart condition, anxiety, or a sleep disorder.
