Water Intake Calculator (Daily)
The practical rule for daily water intake is 30-35 ml of water per kilogram of body weight. For example, the target for a 70 kg person works out to about 2.5 liters. Enter your weight — your daily target is calculated instantly in liters, milliliters and glasses.
Enter your weight — your result appears here instantly.
This is a general guide; your needs rise in a hot climate and with exercise.
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Daily water target by weight
| Weight | Daily target | Glasses (200 ml) |
|---|---|---|
| 50 kg | 1.75 L | ≈ 9 glasses |
| 60 kg | 2 L | ≈ 10 glasses |
| 70 kg | 2.5 L | ≈ 13 glasses |
| 80 kg | 2.75 L | ≈ 14 glasses |
| 90 kg | 3.25 L | ≈ 16 glasses |
| 100 kg | 3.5 L | ≈ 18 glasses |
Values are the 35 ml × weight figure rounded to the nearest quarter-liter; it never drops below 1.5 liters and never exceeds 4 liters.
For informational purposes only; not medical advice. Anyone with kidney, heart or another chronic condition should set their fluid target with a doctor.
Most of your body is made of water; temperature balance, digestion, circulation and how your kidneys work all depend on getting enough fluid. The "2 liters a day" rule is easy to remember but does not fit everyone: it can be too much for a small person and too little for a large or active one. That is why a weight-based figure is a more accurate starting point.
This calculator uses the 35 ml × weight formula — the upper end of the common guideline range — and rounds the result to the nearest quarter-liter so it fits everyday life. The target can shift day to day depending on how much you sweat and what you eat; think of the number as a goal bar, not a strict prescription.
What Raises Your Needs
Hot and humid weather, feverish illness, long journeys, pregnancy and breastfeeding, and any activity that makes you sweat all push your daily needs up. Around 400-800 ml of extra fluid for each hour of moderate exercise is a common recommendation. Increasing water also eases digestion when you move to a higher-fiber diet.
How Do You Know You're Thirsty?
The two simplest signs are the feeling of thirst and the color of your urine: pale straw-yellow is a good sign, while a dark color means you have fallen behind. Headache, fatigue and trouble concentrating are also common symptoms of mild fluid shortage. Spreading intake through the day in small, regular sips is more effective than drinking large amounts all at once.
Make Tracking Easier
The easiest way to hit your water target is to log it as you drink. Running water tracking together with your daily calorie target from one place makes the habit stick; adding a glass each time you fill it takes just a few seconds.
Frequently asked
How is daily water intake calculated?
A practical and widely used method is 30-35 ml of water per kilogram of body weight. This calculator uses the 35 ml × weight formula and rounds the result to the nearest quarter-liter so it fits everyday life. For example, the target for a 70 kg person is about 2.5 liters. Hot weather, exercise and pregnancy increase your needs.
Does 2 liters a day apply to everyone?
No; "8 glasses / 2 liters a day" is a practical average, not a personal figure. Your needs vary with weight, activity, climate and health status. For a 50 kg person 2 liters is more than enough, while for a 100 kg active person it can fall short.
Do tea and coffee count toward water intake?
Partly. Tea and coffee do contribute to your fluid intake; caffeine's mild diuretic effect does not cancel out that contribution. Even so, it is best that water be the main source of your daily target and that sugary drinks be avoided.
How much extra water should I drink when exercising?
A common guideline is roughly 400-800 ml of extra fluid for each hour of moderate exercise; it varies with how much you sweat and the temperature. In long, intense workouts, electrolyte balance matters alongside water.
Can drinking too much water be harmful?
Yes, it is possible to overdo it. Drinking liters of water in a short time can dilute the sodium in your blood (hyponatremia); this is rare but serious. The healthiest approach is to spread intake through the day, using your thirst and the color of your urine as a guide.
Does this target apply with kidney or heart disease?
No. Kidney failure, heart failure and some medication treatments may require fluid restriction; in these cases the daily fluid target must be set with a doctor. The figure on this page is a general guide for healthy adults.
You've set your target — now track it glass by glass.
Logging water in CaloriPanda is a single tap; you can even add it from the home-screen widget.
