Calculate your daily water need by weight, activity, and climate. Get a recommendation in cups and ml. Free water intake calculator.
Your current weight in kilograms
This tool is for informational and educational purposes only. It is not a substitute for professional medical, nutritional, or health advice. For diagnosis, treatment, or personalized guidance, please consult a qualified healthcare provider.
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Staying well hydrated supports energy, digestion, and overall health. Our free water intake calculator estimates your daily fluid need based on body weight, activity level, and optional factors like hot climate or pregnancy. You get a result in milliliters and cups so you can plan how much to drink each day. No sign-up required. For daily calorie and nutrition targets, use our calorie calculator or BMI calculator.
There is no single number for everyone. A common baseline is 30–35 ml of fluid per kilogram of body weight per day—about 0.5–1 oz per pound. For a 70 kg (154 lb) adult, that's roughly 2.1–2.5 liters (about 9–10 cups) per day at rest. Activity, heat, humidity, and health conditions can increase needs. Our calculator uses your weight and activity level to give a personalized daily target. Food and other beverages (e.g. tea, milk) also contribute to fluid intake; the recommendation is for total fluid, not only plain water.
If you are sedentary, the baseline amount is usually enough. Light to moderate activity (e.g. walking, light exercise) increases sweat and breathing, so we add a small multiplier. Active and very active people (regular intense exercise or physical work) need more—often 10–20% or more above baseline. In hot or humid weather, add extra fluid to replace sweat. The calculator lets you choose activity level and optionally add a climate or pregnancy adjustment. Listen to your body: thirst and light-colored urine are good signs of adequate hydration.
We show the result in both ml and cups. One cup is often taken as 240 ml (8 fl oz) in nutrition guidelines; we use 250 ml per cup for easy rounding. A typical glass holds 200–250 ml. Spread your intake across the day rather than drinking a lot at once. Carrying a bottle and sipping regularly helps many people meet their target.
Pregnant and breastfeeding women typically need more fluid; our tool can add an extra amount. People with certain medical conditions (e.g. heart or kidney disease) may need to limit fluid—follow your doctor's advice. In general, healthy adults can use the calculator as a starting point and adjust based on thirst, activity, and climate. For personalized nutrition including fluids, a dietitian can help. Combine this with our calorie calculator and body fat calculator for a fuller picture of your health metrics.
Calorie Calculator – Daily energy need. BMI Calculator – Weight status. Body Fat Calculator – Body composition. Health calculators – Full list.
Daily water need depends on weight, activity, and environment. Our free water intake calculator gives a daily target in ml and cups. Use it as a guide and adjust for thirst and conditions. This tool is for general information only; it is not medical advice. For specific health needs, consult a healthcare provider.
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Daily water need depends on body weight, activity level, and climate. A common baseline is 30–35 ml per kg of body weight per day (about 0. 5–1 oz per pound). For a 70 kg (154 lb) sedentary adult, that's about 2. 1–2. 5 liters (9–10 cups).
Yes. We apply a multiplier based on activity level: sedentary, light, moderate, active, or very active. Higher activity increases fluid loss, so the recommended intake goes up. You can also add extra for hot weather or pregnancy. The result is a daily target; spread intake throughout the day and adjust based on thirst and urine color.
Both are useful. Many guidelines use cups (1 cup ≈ 240 ml or 8 fl oz). Our calculator shows the result in ml and in cups (250 ml per cup for simplicity). A standard glass is often 200–250 ml. Use whichever unit you prefer; the total daily amount is the same.