Personalised Hydration Goal
Fluid requirements vary with body size, activity, environment, and physiological state. Adjust your target with evidence based modifiers.
Recommended intake
2.95 L/day
Total volume
2950 mL/day
Daily breakdown
- Base requirement: 2450 mL
- Activity adjustment: +500 mL
- Climate adjustment: +0 mL
How to Use This Calculator
Set your baseline
Enter weight to determine the baseline fluid need of 35 mL per kilogram per day, with a minimum of 1.5 L.
Adjust for lifestyle
Select activity level and climate. Check pregnancy or breastfeeding if applicable for extra hydration needs.
Track intake
Distribute fluid through the day. Increase intake around exercise and watch urine colour as a quick hydration indicator.
Formula
Base need = max(1500 mL, 35 mL * weight in kg)
Activity adjustment = 0 mL (sedentary), +500 mL (moderate), +1000 mL (intense)
Climate adjustment = -250 mL (cool), 0 mL (temperate), +750 mL (hot)
Pregnancy = +300 mL per day (second or third trimester)
Breastfeeding = +700 mL per day
Total intake = Sum of all adjustments with a minimum of 1500 mL per day
Full Description
Hydration requirements vary widely. This calculator blends weight based guidance with modifiers for activity, climate, and reproductive status. Individual needs may change with medical conditions, diuretic use, or diet. Monitor symptoms and clinical advice, especially when fluid restriction is prescribed.
Frequently Asked Questions
Does all water need to come from drinks?
No. About one fifth of daily hydration can come from foods like fruit, vegetables, and soups. Reduce beverage intake slightly if your diet is water rich.
How should athletes hydrate?
Add 350 to 700 mL for every 30 minutes of exercise and include electrolytes during long or hot workouts.
Is too much water dangerous?
Excess water can cause hyponatremia, particularly with heavy sweating. Avoid drinking more than 1 L per hour and balance fluids with sodium replacement.
What if I am on fluid restriction?
Follow the plan provided by your clinician. This calculator is not suitable for patients with fluid restricted conditions such as heart or renal failure.