Water Intake Calculator | How Much Water Should I Drink?

Find your daily water intake based on body weight and activity level

Get a personalized hydration goal in ounces or liters and adjust for exercise and hot...

When Should You Use This Calculator?

Calculating personalized daily water needs based on weight and activity
Tracking hydration goals over time with persistent history
Adjusting the daily target for exercise duration and intensity
Setting a custom daily goal while keeping the calculated baseline for comparison
Planning hydration strategies with calculation history over time

Key Features:

Weight-based hydration estimate with metric/imperial support
Exercise duration and intensity adjustment
Optional custom daily goal compared against the calculated baseline
Visual equivalency (glasses, bottles, jugs) and progress tracking

Frequently Asked Questions

How much water should I drink daily?

A general rule is 30-35ml per kg of body weight, or roughly half your body weight (lbs) in ounces. The National Academies recommend about 3.7 liters (125 oz) for men and 2.7 liters (91 oz) for women total daily water from all sources. Our calculator adjusts this baseline for your weight and activity level.

Does coffee or tea count towards water intake?

Yes, but pure water is best. While caffeine has a mild diuretic effect, research shows the water content in coffee and tea still contributes net hydration. Water, herbal tea, and low-sugar beverages count most toward your daily goal.

Should I drink more water when exercising?

Yes. During exercise you lose water through sweat — roughly 0.5-1 liter per hour of moderate exercise. Add 1.5-2.5 cups (350-600ml) per 30 minutes of exercise. In hot climates or during intense workouts, increase further. Use the Activity adjustment in this calculator to account for your exercise level.

Can I export my Water Intake Calculator calculations?

Yes. In guest mode you can export your calculations to JSON. Signing in adds PDF and CSV export. Click the export button to download your results — useful for record-keeping, sharing, or importing into other tools.

Does this calculator save my history?

Yes. Your calculation history is saved automatically. As a guest you can keep up to 50 calculations per workspace on your device. Sign in for free to keep up to 100 per workspace and access them from any device.

Is this calculator free to use?

Yes. The Water Intake Calculator is free to use with no sign-up required. A free account adds more calculation history, multiple workspaces, and access to your saved data from any device.

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CalcTrail is a comprehensive free online calculator platform offering a comprehensive collection of specialized calculators for finance, health, academics, engineering, AI tools, and more. All calculators are free to use with no sign-up required. Create an account to save your work, access unlimited calculation history, workspace management, and custom variables.

This calculator is part of CalcTrail's collection of professional-grade tools designed for students, professionals, and anyone who needs accurate calculations. Export your results to PDF, JSON, or CSV formats. All calculations are performed client-side for privacy and speed.

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