Water Intake Calculator
Calculate your daily water intake based on your weight and activity level.
How the Water Intake Calculator works
Use the Water Intake Calculator to estimate your daily water needs. Enter your weight in kilograms into the 'Weight (kg)' field. Select your activity level from the dropdown menu. Choose 'low' for minimal exercise, 'moderate' for regular workouts, or 'high' for intense daily training.
The calculator applies a standard formula: your weight multiplied by 0.033, with an adjustment for your activity level. This provides an estimate of the litres of water you should consume daily. The result also shows the equivalent number of 250ml glasses. This tool helps you understand your personal hydration requirements.
Formula used
water (litres) = weight × 0.033 + activity adjustment
| Symbol | Meaning |
|---|---|
| weight | kilograms |
| activity | low, moderate or high training load |
This covers total fluids including tea, milk and food moisture — not just plain water. Hot weather, illness and pregnancy all push the need higher than the estimate.
Inputs used: Weight (kg), Activity level.
Worked example
Here is a worked example for calculating water intake:
- A person weighs 70 kg and has a moderate activity level.
- Enter '70' into the 'Weight (kg)' field.
- Select 'moderate' from the 'Activity level' dropdown.
- The calculator determines a daily intake of 2.71 litres, which is 11 glasses (250ml).
Result:
- Litres per day: 2.71
- Glasses (250ml): 11
Frequently asked questions
- How much water should I drink a day?
- Daily water intake varies by individual. Factors like weight, activity level, and climate influence your needs. This calculator provides an estimate based on your inputs.
- Does coffee count as water intake?
- No, coffee and other caffeinated beverages do not fully count towards your daily water intake. They can have a diuretic effect.
- What are the signs of dehydration?
- Signs of dehydration include thirst, dark urine, fatigue, and dry mouth. It is important to drink water regularly throughout the day.
- Can I drink too much water?
- Yes, drinking excessive amounts of water can lead to hyponatremia, a condition where sodium levels in the blood become too low. This is rare but can be serious.
- What formula does the Water Intake Calculator use?
- It uses water (litres) = weight × 0.033 + activity adjustment, where weight is the kilograms; activity is the low, moderate or high training load.
- How do I read the result?
- This covers total fluids including tea, milk and food moisture — not just plain water. Hot weather, illness and pregnancy all push the need higher than the estimate.