Water Intake Calculator
Estimate how much water you should drink per day based on your weight, activity level, and climate. This is a simple guideline, not medical advice.
Calculator
Base guideline: ~35 ml per kg body weight. We adjust for activity & heat.
Your daily water target
Hydration needs vary. If you're pregnant, breastfeeding, ill, or have kidney/heart conditions, consult a medical professional.
How this water intake calculator works
The calculator starts with a simple body-weight guideline of about 35 ml of water per kilogram per day. It then adjusts the estimate for activity level and hot or humid climates, where fluid loss through sweating is higher.
Your result is shown in liters, milliliters, and approximate glasses, so it is easier to turn the number into a daily routine.
Daily hydration formula
Base water intake: body weight in kg × 35 ml
Adjusted intake: base intake × activity and climate factor
Important hydration notes
This is a general wellness estimate. Individual needs change with diet, salt intake, medication, medical conditions, pregnancy, breastfeeding, fever, and intense exercise. For long workouts or heavy sweating, electrolytes may matter as much as water.
FAQ
How accurate is this calculator?
It's a practical guideline based on body weight with simple adjustments for activity and heat.
Does coffee or tea count?
They contribute to fluid intake, but water is still the best baseline for hydration.
What if I exercise a lot?
If you sweat heavily, you may need extra fluids and electrolytes. Use the "Active" setting as a baseline.
Is it bad to drink too much water?
Yes—extreme overhydration can be dangerous. Spread intake across the day and drink to thirst.
How to turn your water target into a routine
A daily total is easier to follow when it is split across the day. Start with a glass after waking, add one with each main meal, and keep a bottle nearby during work or training. This prevents trying to drink the full target late in the evening.
Food also contributes to hydration, especially fruits, vegetables, soups, and milk-based drinks. On hot days, during physical work, or after intense workouts, your needs can increase quickly. If you sweat heavily, sodium and electrolytes may also matter.