Caffeine limit.

Worked example

An adult has two 8 oz brewed coffees (2 × 135 mg = 270 mg). The adult maximum is 400 mg, so that is 68% (67.5%, shown as 68%) with 130 mg left. For a child weighing 30 kg the maximum is 30 × 2.5 = 75 mg; two 12 oz soft drinks at the low end of the FDA range (2 × 23 = 46 mg) use 61% of it.

How it works

Health Canada gives a recommended maximum daily intake of caffeine of 400 mg for adults 18 and over, 300 mg for people who are pregnant, planning to become pregnant or breastfeeding, and 2.5 mg per kilogram of body weight for children and adolescents. Health Canada says the figure for children is based on limited data and applies it to adolescents as a precaution. The adult limit is a fixed amount, not a per-kilogram amount.

Drink amounts are the same published averages used on the caffeine half-life page (Health Canada for brewed coffee, FDA for 12 fl oz drinks, as of 2026-10-01). Real drinks vary, so check the label.

Sources (opened 2026-10-08): Health Canada, Caffeine in Foods (page modified 2025-04-02); FDA, Spilling the Beans: How Much Caffeine Is Too Much? (updated 2024-08-28).

FAQ

How much caffeine is too much per day?

Health Canada recommends no more than 400 mg a day for adults 18 and over, 300 mg a day if pregnant, planning to become pregnant or breastfeeding, and 2.5 mg per kg of body weight for children and adolescents.

Is the adult limit based on body weight?

No. The adult maximum is a fixed 400 mg. Only the limit for children and adolescents is set per kilogram of body weight.

How much caffeine is in a cup of coffee?

Health Canada lists 135 mg for 8 oz of brewed coffee. The FDA lists 113 to 247 mg for 12 fl oz. Real amounts vary, so check the label.

Can I stay under the limit and still be sensitive?

Yes. The limit is a guide for healthy people. If you are sensitive to caffeine, lowering your intake may help, and a doctor or pharmacist can advise if you take medication.

See when it clears your system with the caffeine half-life calculator.