75% of people are chronically dehydrated. Use our science-backed calculator to find your personalized daily water goal.
Your Daily Goal
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Why the "8 Glasses a Day" Rule is a Myth
You've probably heard you need to drink 8 glasses of water a day. While this is a catchy guideline, it lacks scientific precision. A 6ft, 250lb linebacker needs significantly more water than a 5ft, 100lb gymnast.
Factors Affecting Hydration Needs
Body Weight: Larger bodies have more blood volume and tissue to hydrate.
Activity Level: You lose water through sweat. For every 30 minutes of intense exercise, you typically need an extra 12oz (350ml) of water.
Climate: Hot or humid weather increases fluid loss through perspiration.
Diet: If you consume a lot of salty foods, you need more water to flush out the excess sodium. Conversely, eating water-rich fruits and veggies (like watermelon) counts towards your intake.
Signs of Dehydration
Don't wait until you are thirsty. Thirst is actually a lagging indicator, meaning you are already dehydrated by the time you feel it.
Dark yellow urine (Aim for pale straw color)
Headache or dizziness
Dry mouth and lips
Fatigue and brain fog
Frequently Asked Questions
Does coffee count?
Yes, but with a caveat. Caffeine is a mild diuretic (makes you pee), but for regular drinkers, the hydrating effect of the water outweighs the diuretic effect. It counts, but plain water is still best.
Can I drink too much water?
Yes, it's called Hyponatremia. It happens when you drink so much water that it dilutes the sodium in your blood to dangerous levels. It is rare but can happen to marathon runners who over-hydrate.
