Calculate how much water you should drink daily based on your weight, age, exercise level, climate, and life stage.
Load profiles to check varying baseline recommendations:
Fill in your physical attributes to predict daily recommended fluid levels.
This captures your custom baseline plus activity, environment, and goal offsets.
How water scales biological metrics, prevents metabolic strain, and powers physical systems.
Water facilitates metabolic reactions, regulates blood circulation, ensures cell volume, keeps joints lubricated, and cushions critical organs. Even a minor 2% drop in hydration levels causes a noticeable drop in mental clarity and physical endurance.
To maintain peak cellular function, space your fluid intake evenly across the day. Avoid chugging massive quantities at once, as your kidneys can process only about 800-1000 ml of water per hour. Sucking small, steady sips is optimal.
Daily water requirement is calculated based on body weight (approx 35 mL per kg) adjusted for sweat fluid losses incurred during physical exercise workouts.
The baseline target is your weight in kilograms multiplied by 35 ml, then adjusted by gender (+300 ml for men, −100 ml for women) and activity level, which adds anywhere from +300 ml (light activity) to +1,500 ml (athlete-level activity).
On top of the baseline, the calculator adds 350 ml for every 30 minutes of exercise, a climate adjustment ranging from −150 ml in cold weather to +700 ml in hot weather, +300 ml for pregnancy or +700 ml for breastfeeding, and +300 ml or +500 ml for weight-loss or muscle-gain goals respectively. The total is clamped between 1,200 ml and 8,000 ml per day.
A 65 kg active woman in a warm climate doing 45 minutes of exercise gets: 65 × 35 = 2,275 ml baseline, −100 ml (female), +1,000 ml (active), +525 ml (45 minutes of exercise at 350 ml per 30 minutes), and +350 ml (warm climate), totaling about 4,050 ml per day.
Your daily total is broken into a 7-slot hydration timeline spread across the day, from a wake-up glass through a small pre-sleep serving, so the target feels achievable rather than overwhelming. Log your actual intake with the Water Tracker & Hydration Log, or pair this with the TDEE Calculator for a complete picture of your daily needs.
Quick answers about how this tool works.
Physical activity increases sweating and respiratory water loss. To compensate, it is recommended to drink an additional 350 to 500 ml (12 to 16 oz) of water for every 30 minutes of moderate-to-intense physical exercise.
Mild dehydration symptoms include dry mouth, fatigue, headache, dizziness, dry skin, and dark yellow urine. Severe dehydration can lead to extreme thirst, confusion, rapid heart rate, and requires immediate medical attention.
A water intake calculator estimates how much water you should drink each day based on factors such as body weight, age, activity level, and environmental conditions. It helps you maintain proper hydration and support overall health.
Proper hydration supports body temperature regulation, nutrient transport, digestion, joint lubrication, kidney function, and overall physical and mental performance. Even mild dehydration can affect energy levels and concentration.
Daily water requirements are commonly estimated using body weight, activity level, climate conditions, and other lifestyle factors. People who exercise frequently or live in hot environments typically require more fluids.
Yes. Most beverages contribute to your daily fluid intake, including coffee, tea, milk, and juice. However, water remains the best choice for hydration because it contains no added sugars or calories.
Yes. Hot and humid weather increases sweat loss, causing your body to require more fluids. Drinking additional water helps replace lost fluids and reduces the risk of dehydration.
Water may support weight management by promoting feelings of fullness and helping reduce unnecessary calorie intake from sugary beverages. It also supports normal metabolism and overall health.
A common sign of adequate hydration is pale yellow urine and regular urination. Persistent thirst, dark urine, dry mouth, fatigue, or headaches may indicate that you need to drink more fluids.
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