Calculate your recommended daily water intake based on your body and activity.
Result
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Daily Water Intake
Liters-
Glasses (250ml)-
Ounces-
💧 Drink water regularly throughout the day, not all at once.
⚙️ How It Works
A water intake calculator estimates your daily hydration needs based on your body weight, activity level, and climate. The most common formula uses body weight as the primary factor, with adjustments for exercise (add 12 oz per 30 minutes of activity) and hot weather. Individual needs vary based on health conditions, diet, and other factors.
Base Intake = Body Weight (lbs) × 0.5 oz | OR: Body Weight (kg) × 33 ml | Exercise Adjustment: +350–500 ml per 30 min of moderate exercise
Editorial Standards
Author
BetterProduct Editorial Team - Editorial standards and multilingual quality review
Reviewed by
Reviewed against hydration guidance and public-health dehydration references.
Updated
April 2026
Best used for
Daily hydration planning and activity-based intake estimates.
Languages checked
7 language editions aligned from the same source formulas.
Use Results Responsibly
Use these numbers as screening estimates, not as a diagnosis.
Age, sex, activity, medications, and medical conditions can change the right interpretation.
If you are pregnant, symptomatic, or managing a condition, confirm decisions with a licensed clinician.
Hydration targets are estimates. Climate, exercise, medications, pregnancy, and kidney or heart conditions can change needs.
Use these numbers as screening estimates, not as a diagnosis.
Age, sex, activity, medications, and medical conditions can change the right interpretation.
If you are pregnant, symptomatic, or managing a condition, confirm decisions with a licensed clinician.
❓ FAQ
Is the '8 glasses a day' rule accurate?
The '8×8 rule' (eight 8-oz glasses = 64 oz/day) is a reasonable starting point but not scientifically precise. The National Academies recommends about 3.7 liters (125 oz) for men and 2.7 liters (91 oz) for women from all beverages and food combined.
Does coffee count toward daily water intake?
Yes, caffeinated beverages like coffee and tea do contribute to hydration despite mild diuretic effects. The water in coffee more than compensates for any fluid loss. However, plain water is still the best hydration source.
What are signs of dehydration?
Early signs include thirst, dark yellow urine, dry mouth, and fatigue. Moderate dehydration causes headaches, dizziness, and reduced concentration. Severe dehydration (medical emergency) causes rapid heartbeat, confusion, and fainting. Pale yellow urine indicates good hydration.
Can you drink too much water?
Yes — overhydration (hyponatremia) occurs when you drink so much water that sodium levels in your blood become dangerously diluted. It's rare in healthy people but can occur during endurance events. Symptoms include nausea, headache, confusion, and in severe cases, seizures.