How Much Caffeine Is Too Much? Daily Limits for Adults, Teens, Pregnancy & Breastfeeding

"Too much" is personal. Body size, medications, health conditions, pregnancy, and how fast your liver clears caffeine all change how much you can handle. Below are the official limits by group, how many drinks it takes to reach them, the warning signs you've overdone it, and what to do if you need to cut back.

How Much Caffeine a Day Is Safe? Official Limits by Group

Health agencies in the U.S., Canada, and Europe have reviewed the research and landed on very similar numbers:

These are upper limits for healthy people, not targets. The FDA stresses that there is "wide variation" in how sensitive people are to caffeine and how fast they eliminate it, and that certain conditions and medications make people more sensitive.

How Many Cups of Coffee Is 400 mg?

The FDA's own shorthand is "about two to three 12-fluid-ounce cups of coffee." But caffeine content varies a lot by drink and brand. Using the FDA's typical ranges, here's roughly how many servings add up to 400 mg:

Two takeaways. First, one large coffee-shop coffee or one high-caffeine energy drink can put you at or above EFSA's 200 mg single-dose level. Second, "a few cups" means very different things depending on the cup. Health Canada lists an 8 oz cup of filter-drip coffee at about 179 mg on average, so three of those (about 537 mg) would already be over the 400 mg daily limit. For brand-by-brand energy drink numbers, see our energy drink caffeine comparison.

Hidden sources of caffeine that count toward your total

According to the FDA, caffeine can show up in energy and protein bars, ice cream, chewing gum, dietary supplements (including pre-workouts), and some over-the-counter medicines. Chocolate adds a little too: Health Canada lists about 7 mg in an ounce of milk chocolate and 25–58 mg in an ounce of unsweetened baking chocolate. The FDA notes your body handles naturally occurring caffeine and added caffeine the same way, so all of it counts.

• Packaged foods must list caffeine in the ingredients when it's added as an ingredient, but the amount is often voluntary.
• Restaurants and coffee shops aren't required to tell you how much caffeine is in what they serve, so ask or check their nutrition pages.
• Check the Drug Facts label on pain relievers and "alertness" tablets for caffeine.

How Much Caffeine Is Too Much for Teens and Kids?

The U.S. has no official caffeine limit for children, but the American Academy of Pediatrics advises against energy drinks for children and teens, and the Dietary Guidelines for Americans say caffeinated drinks should be avoided for children under 2. In children and teens, the FDA notes too much caffeine can cause a faster heart rate, palpitations, high blood pressure, anxiety, and sleep and digestive problems.

Canada and Europe use body-weight limits. Here's what those work out to:

So a single 16 oz energy drink at the high end of the FDA's range (328 mg) is roughly two to three times the limit for a 100 lb teen. Health Canada notes its child limit is precautionary and that healthy older, heavier teens (14–18) may handle caffeine more like adults, but energy drinks still aren't recommended. Read more in energy drinks and heart problems in young adults.

How Much Caffeine Is Safe During Pregnancy and Breastfeeding?

The American College of Obstetricians and Gynecologists (ACOG) says moderate caffeine intake, less than 200 mg a day, does not appear to be a major factor in miscarriage or preterm birth. EFSA also uses 200 mg a day for pregnancy. Health Canada sets 300 mg. Because caffeine's half-life can stretch to about 15 hours late in pregnancy (StatPearls), a cup lasts much longer than usual. That's roughly one 12 oz coffee, depending on strength.

For breastfeeding, the CDC says up to about 300 mg a day (2–3 cups of coffee) usually doesn't harm babies, though newborns and premature babies clear caffeine slowly, so less may be wise. EFSA's figure is 200 mg. Ask your OB, midwife, or pediatrician what's right for you, and see how long caffeine stays in your system for half-life details.

What Are the Signs of Too Much Caffeine?

The FDA lists these as common signs you've had too much:

• Fast heart rate or heart palpitations
• Higher blood pressure
• Insomnia or disrupted sleep
• Anxiety and jitters
• Upset stomach or nausea
• Headache

Sleep is often the first thing to go. EFSA found that even a single 100 mg dose (about 1.4 mg/kg) may affect sleep in some adults when taken close to bedtime. If you regularly get several of these symptoms, the FDA suggests talking with your health care professional about your caffeine intake. Our guide to caffeine, anxiety, and sleep goes deeper.

How Much Caffeine Is an Overdose?

The FDA estimates that toxic effects, such as seizures, can occur with rapid intake of about 1,200 mg of caffeine, which is less than half a teaspoon of pure caffeine powder. That's why the FDA warns that pure and highly concentrated caffeine products "can have serious health consequences, including death." Overdoses from coffee alone are rare because it's hard to drink that much quickly. Most serious cases involve powders, pills, concentrated liquids, or stacking energy drinks and pre-workouts.

StatPearls (NIH's clinical reference) notes that lethal blood caffeine levels have been associated with ingesting about 10 grams or more, though people who are more sensitive can run into severe toxicity at lower doses.

Who Should Limit Caffeine More?

The FDA says body weight, medications, medical conditions, and personal sensitivity all change what "too much" means. Consider staying well under 400 mg, and ask your doctor, if you:

• Take medications that slow caffeine breakdown. The FDA lists drugs such as fluvoxamine and ciprofloxacin as strong inhibitors of CYP1A2, the liver enzyme that clears most caffeine, which can sharply raise caffeine levels.
• Use estrogen-containing birth control, which slows caffeine clearance.
• Have anxiety, panic attacks, or insomnia, which caffeine can worsen.
• Have high blood pressure or a heart rhythm problem. See will quitting coffee lower blood pressure?
• Have liver disease, which can greatly prolong caffeine's half-life.
• Recently quit smoking. Smoking speeds up caffeine breakdown, so after quitting, your usual coffee can feel much stronger.

How to Cut Back If You're Drinking Too Much

If you're over the limit or getting side effects, the FDA advises cutting back gradually. Caffeine withdrawal isn't considered dangerous, but it can be unpleasant. A major review in Psychopharmacology found withdrawal symptoms usually start 12–24 hours after your last dose, peak at 20–51 hours, and last 2 to 9 days. Headache and fatigue are the most common.

• Add it up first. Track every source for 3 days, including tea, soda, pre-workout, and chocolate.
• Cut about 10–25% every few days instead of stopping cold turkey. Swap one drink for half-caf, then decaf.
• Set a caffeine curfew. Keep caffeine out of the 8–9 hours before bed.
• Downsize. Go from a large to a small, or from a 16 oz energy drink to a smaller can.
• Keep the ritual. Try one of these coffee alternatives.

Our guides to quitting caffeine without headaches and cold turkey vs. gradual withdrawal walk through a full taper.

Frequently Asked Questions

Is 400 mg of caffeine a day too much?

For most healthy adults, no. The FDA, Health Canada, and EFSA all treat up to 400 mg a day as not generally linked to harmful effects. It is too much during pregnancy (under 200 mg is advised) and for children and teens, and it may be too much for you if you're sensitive, take certain medications, or have heart, anxiety, or sleep problems.

Is 200 mg of caffeine a lot?

It's a moderate dose, about one large brewed coffee. EFSA says single doses up to 200 mg are of no safety concern for healthy adults. It's also roughly the full daily limit advised during pregnancy.

Is 500 mg of caffeine too much?

It's above the 400 mg daily amount cited by the FDA for healthy adults, so it raises the chance of side effects like jitters, a fast heartbeat, anxiety, upset stomach, and poor sleep. Taking that much at once is more likely to cause problems than spreading it out.

How much caffeine can kill you?

StatPearls notes lethal blood levels have been linked to ingesting about 10 grams or more of caffeine, though sensitive people can have severe toxicity at lower doses. The FDA estimates toxic effects like seizures can start with rapid intake of about 1,200 mg, which is why pure caffeine powders are so dangerous.

How much caffeine should a teenager have?

Health Canada recommends no more than 2.5 mg per kilogram of body weight a day for children and teens, and EFSA uses 3 mg/kg. For a 100 lb (45 kg) teen, that's about 113–136 mg a day. The American Academy of Pediatrics advises against energy drinks for children and teens.

How many cups of coffee a day is too much?

For most adults, more than about two to three 12 oz cups of brewed coffee a day goes over 400 mg, according to the FDA. Strong coffee-shop brews can hit that limit sooner.

What should I do if I had too much caffeine?

Stop taking in more caffeine, drink water, eat something, and wait. Symptoms usually ease over a few hours as levels fall. Call 911 for chest pain, an irregular or very fast heartbeat, trouble breathing, confusion, or a seizure. In the U.S., call Poison Control at 1-800-222-1222 with questions.

Sources

• U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? (400 mg/day, drink ranges, 1,200 mg toxicity estimate, symptoms, hidden sources, children and teens).
• European Food Safety Authority. Caffeine and Scientific Opinion on the safety of caffeine, EFSA Journal, 2015 (200 mg single dose, 400 mg/day, pregnancy and lactation, 3 mg/kg for children, 100 mg and sleep).
• Health Canada. Caffeine in Foods (recommended maximum daily intakes, 2.5 mg/kg for children and teens, average caffeine in foods and drinks).
• American College of Obstetricians and Gynecologists. Moderate Caffeine Consumption During Pregnancy (Committee Opinion No. 462).
• CDC. Maternal Diet and Breastfeeding (caffeine).
• StatPearls. Caffeine Toxicity and Caffeine. NCBI Bookshelf.
• U.S. FDA. Examples of Drugs that Interact with CYP Enzymes (CYP1A2 inhibitors).
• Juliano LM, Griffiths RR. A critical review of caffeine withdrawal. Psychopharmacology, 2004.
• America's Poison Centers. Poison Help: 1-800-222-1222.