Drink comparison
Drink Hydration Index calculator
Compare beverage context and log the actual volume. A research hydration index is not a personal water-equivalence calculator.
Hydration comparison
500 ml of beverage
500 ml of water is the volume entered. Simple baseline.
Important limitation
BHI research measured short-term urine output after 1 L in 72 healthy, hydrated men. It does not convert drinks into effective millilitres or show long-term health benefit. Milk retained more fluid in that experiment; alcohol is not a hydration strategy.
Shareable stat card
Compare beverage context and log the actual volume. A research hydration index is not a personal water-equivalence calculator.
Open milk hydration card
Frequently asked
Can milk hydrate better than water?
BHI research measured short-term urine output after 1 L in 72 healthy, hydrated men. It does not convert drinks into effective millilitres or show long-term health benefit. Milk retained more fluid in that experiment; alcohol is not a hydration strategy.
Does coffee count as water?
Yes, coffee contributes fluid, especially for habitual caffeine users. Very large caffeine doses can be mildly diuretic, so water is still the cleaner default.
Does beer hydrate you?
Beer contains water, but alcohol suppresses vasopressin and increases urine output. It should not be used as a hydration strategy.
Sources
- 1.Maughan et al., Beverage Hydration Index, AJCN 2016 — A controlled short-term study in 72 healthy, hydrated men compared urine output after 1 L of different drinks. Milk and ORS showed greater short-term retention; BHI is not a conversion to effective beverage volume or proof of long-term benefit.AJCN 103(3):717–723; abstract, methods and results (2-hour BHI and 4-hour cumulative urine)
- 2.Killer, Blannin & Jeukendrup, PLOS ONE 2014 — A three-day crossover trial in 50 habitual male coffee drinkers compared four 200 ml coffee servings with water and found no significant differences in hydration markers; not a general caffeine safety threshold.
- 3.UK NHS (Eatwell Guide) — Suggests about 6–8 glasses (roughly 1.5–2 L) of fluid a day — water, lower-fat milk, tea and coffee all count toward the total.