Daily Water Intake Calculator
Staying hydrated is essential for energy, skin health, and focus. Calculate exactly how much water you should drink based on your body weight, activity, and climate.
Daily Goal
Liters per day
Activity Adjust
Exercise compensation
Climate Adjust
Hot weather fluid
Weight Based
Personalized math
Is 8 Glasses Enough?
The old "8 glasses a day" rule is a myth. Your water needs depend on your body size, how much you sweat, and where you live.
The Science of Hydration
Water makes up about 60% of your body weight. Every system in your body depends on water. Lack of water can lead to dehydration, a condition that occurs when you don't have enough water in your body to carry out normal functions. Even mild dehydration can drain your energy and make you tired.
Personalized Calculation
We calculate roughly 35ml per kg of body weight as a baseline.
Exercise Compensation
We add fluid recommendations for every 30 minutes of moderate exercise.
Climate Factor
Hot or humid weather can make you sweat and requires additional fluid intake.
Custom Inputs
Input your specific weight and activity duration to get a number tailored to your lifestyle, not a generic average.
Unit Converter
Whether you think in Liters, Cups, or Ounces, we display the results in the format you understand best.
Intake Breakdown
See how much of your water need comes from your size versus your daily gym session.
Why Use Our Water Calculator?
Simple & Fast
No complicated forms. Just 3 questions to get your daily target.
Activity Smart
We automatically add water to your goal if you tell us you're working out.
Visual Goals
We translate "Liters" into actual glasses of water, making it easier to visualize.
Completely Free
Access unlimited calculations without signing up or paying a fee.
Calculate Your Daily Water Goal
Enter your stats to find your optimal fluid intake.
How to Use the Water Calculator
Get your personalized hydration plan in seconds.
Enter Weight & Activity
Start by selecting your preferred units. Enter your current weight. Then, estimate how many minutes of exercise you do on an average day.
Adjust for Climate
Select "Hot/Humid" if you live in a warm region or are currently experiencing a heatwave. This adds extra fluid to compensate for sweating.
View Breakdown
See your total daily requirement in liters or ounces, along with a visual representation of how many glasses you need to drink.
Daily Water Recommendations by Age
General guidelines provided by the Institute of Medicine (IOM).
*Total water includes fluids from water, beverages, and food.
Applications of This Tool
Who needs to track their water intake?
Weight Loss Aid
Drinking water before meals can help you feel fuller and eat less. It also temporarily boosts your metabolism. Use this calculator to ensure you aren't mistaking thirst for hunger.
Athletic Performance
Muscle fatigue occurs when cells don't have enough fluids. Athletes use calculators like this to plan hydration strategies before, during, and after workouts to maintain peak performance.
Dehydration vs. Hydration
Why hitting your daily goal matters for your body.
Signs of Dehydration
Even mild dehydration (1-2% loss of body weight) can affect brain function.
- Persistent headaches & dizziness
- Dark yellow urine
- Fatigue and low energy
- Dry skin and lips
Benefits of Hydration
Keeping your fluid levels up boosts performance and health.
- Regulates body temperature
- Lubricates joints
- Improves skin complexion
- Aids in weight loss & digestion
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Frequently Asked Questions
Does coffee count towards my intake?
Yes, but with a caveat. While coffee and tea provide fluids, they also have a mild diuretic effect. Water is always the best source, but moderate coffee/tea consumption contributes to your daily total.
Can I drink too much water?
Yes, it's called hyponatremia. It happens when you drink so much water that sodium levels in your blood become diluted. However, this is rare and usually only happens to endurance athletes drinking excessive amounts in short periods.
How do I know if I'm hydrated?
The easiest test is urine color. It should be pale yellow or clear. If it is dark yellow or amber, you need to drink more water.
Does food count?
Absolutely. About 20% of daily fluid intake usually comes from food, especially fruits and vegetables like watermelon, cucumber, and oranges.