How much water should I drink a day?

The National Academies recommend 3.7 liters (125 oz) for men and 2.7 liters (91 oz) for women — but this includes water from all sources. Your personal needs vary based on weight, activity level, climate, and health status.

Does coffee count toward daily water intake?

Yes, caffeinated beverages do contribute to hydration, despite the mild diuretic effect. However, you'll need slightly more total fluid to compensate. This calculator adds an adjustment for caffeine drinkers.

Does exercise increase water needs?

Significantly. You lose 0.5–1 liter per hour during moderate exercise. Intense exercise in heat can double that. Always drink before, during, and after exercise.

What are signs of dehydration?

Dark yellow urine, thirst, headaches, fatigue, dizziness, and reduced focus. Mild dehydration of just 1-2% body weight can impair cognitive performance.

Water Intake Calculator

Calculate your personalized daily water intake based on your weight, activity level, climate, and health factors. Get results in oz, cups, or liters.

About You

Biological Sex

Age

Weight

Activity Level

Climate

Additional Factors

Drinks caffeine daily (coffee, tea, soda)

Currently pregnant

Currently breastfeeding

Daily Water Recommendation

157 oz

20 × 8oz glasses · ~9.8 oz/hr

Daily Glasses

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What to actually drink

126 oz from beverages

The remaining ~31 oz comes from food

Adjustments Applied

Activity (moderate)+24 oz

Climate (moderate)+8 oz

Hydration Tips

💧Start every morning with a large glass of water before coffee.
💧Drink a glass before each meal — it also aids portion control.
💧Keep a reusable water bottle visible on your desk.
💧Eat hydrating foods: cucumber (96% water), watermelon (92%), oranges (88%).
💧Set hourly reminders to drink ~9.8 oz (290 ml).
💧Your urine should be pale yellow (straw-colored) — dark yellow = drink more water now.