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Water Intake Calculator

How much water should you drink daily? Get a personalized hydration target based on your weight, activity level, and climate for optimal fitness performance.

How to Calculate Your Daily Water Needs by Body Weight

A commonly used baseline for daily water intake is 30 to 35 millilitres per kilogram of body weight. For a 70 kg person, that translates to roughly 2.1 to 2.5 litres per day. However, this is just a starting point. Your actual needs increase with physical activity, hot or humid weather, high altitude, and certain health conditions. Pregnant and breastfeeding women also require additional fluids. Foods with high water content like fruits, vegetables, and soups contribute to your daily intake as well. The colour of your urine is a practical hydration indicator: pale straw yellow generally means you are well hydrated, while dark yellow suggests you need to drink more.

Hydration and Exercise Performance: The Proven Link

Even mild dehydration of 1 to 2 percent of body weight can measurably reduce physical and cognitive performance. Studies show that dehydrated athletes experience reduced strength, endurance, and reaction time. During exercise, aim to drink 150 to 250 ml every 15 to 20 minutes, and replace each kilogram of body weight lost during a workout with approximately 1.5 litres of fluid. For sessions lasting over an hour, adding electrolytes helps maintain sodium and potassium balance. Post-workout hydration is equally important for recovery, as water supports nutrient transport to muscles and waste removal from tissues.

Frequently Asked Questions

How much water should I drink when exercising?▼
Drink 400 to 600 ml of water two hours before exercise, 150 to 250 ml every 15 to 20 minutes during your workout, and enough afterward to replace any weight lost. For intense sessions over one hour, consider an electrolyte drink to replace lost sodium and potassium.
Can you drink too much water?▼
Yes, although it is rare. Drinking excessive amounts of water in a short period can lead to hyponatremia, a dangerous drop in blood sodium levels. This is most common during endurance events. For most people, thirst and urine colour are reliable guides to avoid both under- and over-hydration.
Does coffee count as water intake?▼
Yes, moderate coffee consumption contributes to your daily fluid intake. While caffeine has a mild diuretic effect, studies show that the fluid in coffee more than compensates for any extra urine output. However, heavily sweetened or high-calorie coffee drinks should not be your primary hydration source.

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