Do Coffee and Tea Count Toward Daily Hydration?

How drinks affect hydration

Every drink contains water that enters your body. Researchers compared how well different drinks are retained, building a “beverage hydration index”. Tea and coffee did not differ significantly from water, while drinks such as milk and oral rehydration solutions were retained a little longer.

Caffeine — what is known

Caffeine can increase urine output, but the effect is mild and short-lived, and the body adapts with regular coffee drinking. In a study of men who drink coffee regularly, 4 cups of coffee a day for 3 days produced no worse hydration markers than the same amount of water. The conclusion applies to moderate intake — it should not be extended to very large amounts of caffeine.

Common myths

• “Coffee always dehydrates.” No — in moderate amounts it counts toward your fluids.
• “You must drink an extra glass of water for every coffee.” There is no evidence for this; water is a good habit but not a “compensation”.
• “Herbal tea does not count.” It does — and it contains no caffeine (depending on the blend).
• “Alcohol hydrates too.” Do not count on it as a source of fluids: alcoholic drinks increase urine output.

EFSA caffeine limits

According to EFSA, adults can safely consume up to 400 mg of caffeine a day, with single doses up to about 200 mg. Pregnant and breastfeeding women should not exceed 200 mg a day. For orientation, a cup (200 mL) of brewed coffee usually contains around 80 mg of caffeine, though content varies widely, and energy drinks and some supplements add more.

Unsweetened and sweetened drinks

The bigger issue is not caffeine but add-ins. The WHO recommends limiting free sugars to under 10% of energy intake, ideally under 5%. Sweetened coffee, tea with sugar, syrups and energy drinks can add a lot of sugar. Water remains the best everyday choice, and coffee and tea are best without sugar or with little.

When to be careful

• in pregnancy and while breastfeeding (limit 200 mg a day),
• with high blood pressure, heart-rhythm problems, anxiety or insomnia — ask your doctor,
• in children and teenagers, especially with energy drinks,
• in the evening if caffeine disturbs your sleep,
• if you take medicines that interact with caffeine.

A practical example

Two cups of coffee (400 mL), a mug of tea (250 mL), soup at lunch and 3–4 glasses of water through the day all count toward fluids, and with caffeine at about 160–200 mg you stay within the limits. In the WODA app you can log the water you drink to see how much plain water you have alongside coffee and tea. How much fluid you need: How Much Water Should You Drink Per Day?.

Frequently asked questions