What Is the Daily Caffeine Limit? | How Many Cups of Coffee Is 400 mg, and Limits by Body Weight
“How many cups of coffee a day is safe?” can be answered using the guidance published by public health agencies. Healthy adults should stay within 400 mg a day and 200 mg at a time, but for children the limit depends on body weight, and during pregnancy it is halved. This guide covers the daily limit for each group, how many cups of coffee, tea or energy drinks 400 mg and 200 mg represent, how to work out your own limit from body weight, the symptoms of too much caffeine, and the hidden sources people tend to overlook.
Daily caffeine limits by group
Japan has no official upper limit for caffeine intake. That is why materials from Japan's Ministry of Agriculture, Forestry and Fisheries and its Food Safety Commission cite values from overseas agencies such as Health Canada and the European Food Safety Authority (EFSA). The main guidelines are as follows.
| Group | Daily limit | Single dose | Source |
|---|---|---|---|
| Healthy adults | 400 mg | 200 mg (about 3 mg per kg of body weight) | Health Canada, EFSA |
| Pregnant or breastfeeding | 200 mg | 200 mg | EFSA (Health Canada and WHO: 300 mg) |
| Children 13 and over | 2.5 mg per kg of body weight | 3 mg per kg of body weight | Health Canada |
| Ages 10 to 12 | Up to 85 mg (2.5 mg per kg) | 3 mg per kg of body weight | Health Canada |
| Ages 7 to 9 | Up to 62.5 mg | 3 mg per kg of body weight | Health Canada |
| Ages 4 to 6 | Up to 45 mg | 3 mg per kg of body weight | Health Canada |
These figures mean “up to this amount, no harm to health is expected”, not that you should consume this much. People who are sensitive to caffeine, who have heart conditions or anxiety disorders, or who take medication can be affected by smaller amounts. Pregnancy and breastfeeding are covered in detail in caffeine during pregnancy and breastfeeding.
How many cups is 400 mg or 200 mg? A chart by drink
Here is how many servings of common drinks make up 400 mg a day (healthy adults) and 200 mg (pregnant or breastfeeding). Figures are truncated, not rounded up.
| Drink (serving) | Caffeine | Up to 400 mg | Up to 200 mg |
|---|---|---|---|
| Drip coffee, 150 ml | About 90 mg | 4.4 cups | 2.2 cups |
| Instant coffee, 140 ml (2 g powder) | About 80 mg | 5.0 cups | 2.5 cups |
| Canned coffee, 185 g | About 102 mg | 3.9 cans | 1.9 cans |
| Espresso, 1 shot | About 80 mg | 5.0 cups | 2.5 cups |
| Gyokuro green tea, 60 ml | About 96 mg | 4.1 cups | 2.0 cups |
| Black tea, 150 ml | About 45 mg | 8.8 cups | 4.4 cups |
| Sencha green tea, 120 ml | About 24 mg | 16.6 cups | 8.3 cups |
| Oolong tea, 500 ml bottle | About 100 mg | 4.0 bottles | 2.0 bottles |
| Energy drink, 250 ml | About 80 mg | 5.0 cans | 2.5 cans |
| Energy drink, 355 ml | About 142 mg | 2.8 cans | 1.4 cans |
| Cola, 350 ml | About 39 mg | 10.3 cans | 5.1 cans |
With drip coffee, about 4 cups a day is a rough guide, or 2 during pregnancy. The limit, however, is the total caffeine you take in that day. Three cups of coffee plus a bottle of oolong tea already come to about 370 mg. If you drink coffee from a mug (around 300 ml), one mug is about 180 mg, so halve the cup count. The source figures for each drink are listed in caffeine content by drink.
Calculating your daily limit and single dose from body weight
For children, the daily limit is 2.5 mg per kg of body weight and the single dose 3 mg per kg. For adults too, treating the single dose as the lower of 3 mg per kg and 200 mg makes it easier to match your build.
| Body weight | Children 13+: daily limit | Single dose (weight × 3 mg) | Adult single dose |
|---|---|---|---|
| 30 kg | 75 mg | 90 mg | - |
| 40 kg | 100 mg | 120 mg | 120 mg |
| 50 kg | 125 mg | 150 mg | 150 mg |
| 60 kg | 150 mg | 180 mg | 180 mg |
| 70 kg | 175 mg | 210 mg | 200 mg (cap) |
For a 40 kg child, the daily limit of 100 mg is exceeded by a single 355 ml energy drink (about 142 mg). Teenagers who drink energy drinks for sports or exam study need to be especially careful. The 45 mg limit for 4 to 6-year-olds is almost used up by one 350 ml can of cola (about 39 mg).
Watch the amount at one time, not just the daily total
Even within 400 mg a day, taking a lot in a short time makes the level in your body rise sharply. EFSA states that for healthy adults, up to 200 mg at a time (about 3 mg per kg of body weight) raises no health concerns.
- A 355 ml energy drink (about 142 mg) followed by one caffeine tablet (100 mg) comes to about 242 mg in one go
- A large mug of coffee (about 180 mg) is close to the single-dose guide on its own
- Stacking a caffeinated supplement and an energy drink before exercise easily takes you over 200 mg without noticing
Caffeine peaks in your body about an hour after you drink it, so adding “one more because it isn't working” is risky. Wait until it takes effect before deciding.
Symptoms of too much caffeine
Too much caffeine can cause the following symptoms. They are more likely the larger the amount and the smaller the person.
- Palpitations, a fast pulse, trembling hands
- Restlessness, anxiety, irritability
- Trouble sleeping or light sleep
- Nausea, stomach discomfort, diarrhoea
- Headache, dizziness
People who have been taking a lot of caffeine every day may get withdrawal symptoms such as headache, fatigue, drowsiness and poor concentration if they stop suddenly. When cutting down, reduce gradually over a few days to a week and switch to decaf or barley tea to make it easier.
Checking today's total and how many more cups you can have
- 1
Enter what you drank today
Choose from 20 items such as coffee, tea, energy drinks, chocolate and tablets, and enter the amount. If a product shows its caffeine content, enter the mg directly under “Other”.
- 2
Choose the group and body weight
Choose from “Healthy adult”, “Pregnant or breastfeeding”, “Child 13 or over” and “Ages 4 to 12”. For a child, entering body weight gives a daily limit of 2.5 mg per kg.
- 3
See your daily total and what is left
It shows today's total and how many mg remain before the limit. Choose your next drink under “If I have one more” to see whether it would still keep you within the limit. If the amount from one drink exceeds the single-dose guide (weight × 3 mg, or 200 mg for adults), that drink is flagged.
You can also check how much will have worn off by the evening. The relationship with bedtime is explained in how many hours before bed to stop drinking coffee.
FAQ
- How many cups of coffee a day is safe?
- Using the 400 mg daily guide for healthy adults (Health Canada, EFSA), that is about 4 cups of drip coffee (about 90 mg per 150 ml), or about 2 large mugs (around 300 ml). Add up caffeine from tea, energy drinks and other drinks as well.
- How much is 400 mg of caffeine?
- It is equivalent to about 4.4 cups of drip coffee, 3.9 cans of canned coffee (185 g), 2.8 cans of a 355 ml energy drink, 8.8 cups of black tea or 16.6 cups of sencha. Amounts vary by product, so check the can or bottle label.
- How much caffeine can children have?
- Health Canada's guidance is up to 2.5 mg per kg of body weight a day: 45 mg for ages 4 to 6, 62.5 mg for 7 to 9 and 85 mg for 10 to 12. A 40 kg child's limit is 100 mg a day, which one energy drink can exceed.
- How much caffeine is safe at one time?
- For healthy adults, up to 200 mg at a time (about 3 mg per kg of body weight) raises no health concerns (EFSA). For someone weighing 60 kg, 180 mg is the guide. Avoid stacking doses in a short time, such as an energy drink followed by a caffeine tablet.
- Does Japan have a caffeine intake standard?
- Japan has no official daily upper limit. The Ministry of Agriculture, Forestry and Fisheries and the Food Safety Commission cite guidance from overseas agencies such as Health Canada and the European Food Safety Authority (EFSA), and those values are generally used.
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