Water Intake Calculator

Find out how much water you should drink each day based on your weight, activity level, and climate.

Tools

Parameters

kg

Little or no exercise, desk job

Result

Daily water intake

2,450

ml / day

glasses

10

approx. glasses (250 ml each)

Increase by ~500 ml for every 30 min of exercise.

Estimate your basal metabolic rate and see how many calories your body burns at rest each day.

BMR Calculator →

Disclaimer: This estimate is a general guideline based on body weight, activity, and climate. Individual needs vary. Consult a healthcare professional for personalised advice.

How much water should you drink?

A common starting point is 35 ml of water per kilogram of body weight per day. Activity and heat both increase fluid loss, so the calculator adjusts upward for more active or warmer conditions.

The 8 glasses a day rule is a rough heuristic. Your actual needs depend on your size, how much you sweat, the foods you eat, and whether you drink other hydrating beverages throughout the day.

How the calculation works

  • Base intake: 35 ml × body weight in kg.
  • Activity adjustment: +10% for lightly active, +20% for moderately active, +30% for very active.
  • Climate adjustment: +10% for hot or humid conditions.
  • Result is rounded to the nearest 50 ml and converted to 250 ml glasses.

FAQ

Does coffee or tea count towards my water intake?

Caffeinated drinks have a mild diuretic effect but still contribute to hydration. Tea and coffee can count, but plain water remains the best source.

Should I drink more on exercise days?

Yes. A general rule is to add about 500 ml for every 30 minutes of moderate exercise. Drink before, during, and after your workout.

Is it possible to drink too much water?

Hyponatraemia (water intoxication) is rare but real. For most people it is not a concern, but endurance athletes should be careful not to over-hydrate during long events.

Why does climate affect water needs?

Hot or humid conditions increase sweat rate, leading to higher fluid loss even at rest. Air conditioning and cold climates can have the opposite effect.