Does it count?
Does milk count as water?
Quick answer
Yes, milk counts as water — and then some. Milk is about 87% water, and because it contains electrolytes, protein, and a little fat, it stays in the body longer than plain water. The Beverage Hydration Index ranks milk and oral rehydration solutions among the most hydrating drinks you can have.
The short answer
Counts (and then some)
Milk is more hydrating than plain water, gram for gram.
Milk is essentially water with electrolytes, protein, sugar (lactose), and a little fat dissolved in it. That composition slows how quickly it leaves the body, which is why researchers use the Beverage Hydration Index to show that milk keeps you hydrated longer than water.
A 1 glass (240 ml) of this drink is roughly 87% water. So in fluid terms, it contributes meaningfully to your day — but the other ingredients matter too. The numbers below compare it to a few other common drinks.
| Serving | Water content | Caffeine |
|---|---|---|
| 1 glass (240 ml) | 87% | — |
| 1 cup (240 ml) (coffee) | 98% | 95 mg |
| 1 mug (240 ml) (tea) | 99% | 40 mg |
| 1 can (355 ml) (soda) | 90% | 35 mg |
The bottom line
Milk is one of the most hydrating drinks there is — it absolutely counts, and may even do a better job than water.
Whatever drinks you choose, the goal is the same: hit your total daily fluid target, mostly from water. Use the calculator to find that number for your body.
Find your daily water goal
Now you know what counts — see how much you actually need based on your weight, activity, and climate.
Frequently asked
Is milk more hydrating than water?
On the Beverage Hydration Index, skim and whole milk both outperform plain water for hydration over the following four hours. The electrolytes (sodium, potassium) and protein help the body retain the fluid, so less is lost to urine.
Does plant milk hydrate you the same way?
Plant milks vary. Most are about 90% water and contribute fluid, but they typically have fewer electrolytes than dairy milk unless they're fortified, so they hydrate a little less effectively than cow's milk. They still count toward your daily water.
Should I count milk toward my water goal?
Yes, you can count it. A glass of milk is roughly 210 ml of water. If you drink several glasses a day, they genuinely add up — just remember milk also brings calories and protein, unlike plain water.
Sources
- 1.Maughan et al., Beverage Hydration Index, AJCN 2016 — Milk and oral rehydration solutions stay in the body longer than plain water, hydrating more effectively.
- 2.U.S. National Academies (IOM/NAM), 2005 — Adequate total water intake of about 3.7 L/day for men and 2.7 L/day for women, including water from food and all beverages.