💧 Water Intake Calculator
Calculate your personalised daily water intake based on your weight, activity level, and climate. Stay hydrated and understand exactly how many glasses of water you need each day.
How the Calculation Works
How to Use This Calculator
-
1Enter Your WeightChoose metric (kg) or imperial (lbs) and enter your body weight.
-
2Select Activity LevelHonest self-assessment of your daily exercise helps fine-tune your hydration target.
-
3Choose Your ClimateHot and humid environments increase water loss through sweat.
-
4Add Extras if NeededTick pregnancy or breastfeeding for the additional intake recommended by health guidelines.
Example Calculation
Person weighing 70 kg, active lifestyle, living in a hot climate:
Frequently Asked Questions
General guidelines suggest around 2–3.7 litres per day for adults, but individual needs vary based on body weight, activity level, climate, and health status. A common rule of thumb is 0.033 litres per kg of body weight. This calculator personalises that baseline for you.
Yes, caffeinated beverages like coffee and tea do contribute to hydration, contrary to the old myth. Modern research shows that the mild diuretic effect of caffeine is offset by the water content of the drink. However, plain water remains the best source, and sugary or alcoholic drinks do not count.
Early signs include thirst, dark yellow urine, headache, fatigue, and reduced concentration. Severe dehydration can cause dizziness, rapid heartbeat, confusion, and fainting. The easiest indicator is urine colour — pale yellow means well hydrated; dark amber means drink more water.
Yes. Overhydration (hyponatremia) occurs when you drink water faster than your kidneys can excrete it, diluting sodium levels in the blood. It is rare in everyday life but can occur in endurance athletes who drink excessive plain water without electrolytes. Listen to your body — drink when thirsty.
Related Calculators
Calorie Calculator
Calculate your daily calorie needs based on age, gender, height, weight, and activity level.
BMR Calculator
Calculate your Basal Metabolic Rate — the calories your body burns at rest.
Protein Intake Calculator
Calculate your daily protein needs based on weight, activity level, and fitness goal.