OmniCalcsWater Intake Calculator
How much water should you drink each day? Get a personalized target from your weight, exercise and climate.
How to Use This Calculator
Enter your weight, daily exercise and climate. The result is a daily hydration target that includes water from drinks — food adds roughly 20% more.
- Thirst, dark urine and fatigue are practical signs to drink more.
- During exercise, add about 240-360 ml (8-12 oz) per 30 minutes.
- This is a general guideline, not a medical prescription.
Frequently Asked Questions
Is the 8-glasses rule accurate?
Not for everyone. Needs scale with body size, activity and climate — which is exactly what this calculator personalizes.
Does coffee count as water?
Yes. Caffeine is a mild diuretic, but caffeinated drinks still contribute to total fluid intake.
Can I drink too much water?
In extreme amounts, yes — but it is rare. Listen to thirst and don't force beyond comfort.
Who needs more than average?
Athletes, people in hot climates, pregnant and breastfeeding women all have higher needs.
Practical Example
Suppose you weigh 80 kg, exercise moderately, and live in a warm climate:
- Base intake ≈ 80 × 33 ml ≈ 2.6 L/day
- With exercise + climate adjustment ≈ 3.2–3.5 L/day
That's roughly 11–12 glasses of water per day.
What Your Results Mean
- Daily water target — your personalized total fluid intake from all drinks.
- Glasses — a practical way to track it (250 ml per glass).
- Food provides some fluid too; adjust down slightly if you eat many water-rich foods.