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Health & Fitness Calculator
Water Intake Calculator: Daily Hydration Target
Build an adult daily hydration plan from body weight, exercise, sweating, temperature, humidity and life stage, then see liters, bottles, a schedule and a private daily tracker.
Water intake by body weight
A practical daily range often starts with body weight, then adjusts for activity and environment.
- A common planning range is about 30 to 40 ml per kg per day.
- Exercise, hot weather, humidity, fever, and sweating can increase needs.
- Food and other drinks can contribute to total fluid intake.
Hydration formula example
Use the result as a target range rather than a strict rule.
- 70 kg x 35 ml/kg = 2,450 ml per day.
- 2,450 ml is about 2.45 liters.
- Adjust based on thirst, urine color, training, heat, and health guidance.
When to be careful
More water is not always better for every person.
- Kidney, heart, pregnancy, or medication-related fluid limits require medical advice.
- Long endurance exercise may require electrolytes, not just water.
- Extreme overhydration can be dangerous.
Related health calculators
These tools work with a daily hydration and nutrition plan.
- Protein Intake Calculator
- Calorie Calculator
- BMI Calculator
- Heart Rate Calculator
- Heat Index Calculator for hot-weather planning
Water Intake Calculator FAQ
How much water should I drink per day?
A common estimate is about 30 to 40 ml per kg of body weight per day, adjusted for activity, heat, diet, and health needs.
How do I calculate water intake by weight?
Multiply body weight in kilograms by a target ml/kg. For example, 70 kg x 35 ml/kg = 2,450 ml, or 2.45 liters.
Do coffee and tea count toward water intake?
They can contribute fluid, but the best answer depends on total diet, caffeine tolerance, and health situation.
Should I drink more water when exercising?
Usually yes, especially with heat or heavy sweating. Longer sessions may also require electrolytes.
Is this water intake calculator medical advice?
No. It is a planning estimate. Follow medical guidance if you have a health condition or fluid restriction.
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