Water Intake Calculator — How Much Water Should You Drink Per Day?

Calculate your personalized daily water intake based on body weight, activity level, climate, age, and health goals — with pregnancy and breastfeeding support, a urine-colour hydration guide, and a bottle tracker.

How to use the Water Intake Calculator

  1. Enter your body weight: Select metric (kg) or imperial (lbs) and enter your current body weight using the slider.
  2. Set age and gender: Enter your age and select your gender.
  3. Choose activity level: Select how active you are — from sedentary to athlete.
  4. Select your climate: Choose your environment — cold, moderate, hot, humid, or high altitude.
  5. View your result: See your daily water intake in liters, ml, oz, cups, and glasses, plus a drinking schedule.

Frequently Asked Questions

How much water should I drink per day?

The standard guideline is 30–35 ml per kg of body weight. For a 70 kg adult, that's approximately 2.1–2.5 liters. Your actual needs vary based on age, gender, activity level, climate, and health goals.

How much water should I drink per day by weight?

Multiply your weight in kg by 30–35 ml. A 60 kg person needs ~1.8–2.1 L; an 80 kg person needs ~2.4–2.8 L; a 100 kg person needs ~3.0–3.5 L. In imperial units: multiply your weight in lbs by 0.5–0.67 to get daily fluid ounces.

Is the '8 glasses a day' rule accurate?

The 8×8 rule (8 glasses of 8 oz ≈ 1.9 liters) is a useful baseline for a sedentary adult in a moderate climate, but it doesn't account for individual body weight, activity level, climate, or health goals. This calculator uses validated formulas for a more personalized result.

Does coffee or tea count toward my daily water intake?

Yes — caffeinated drinks still contribute to hydration despite their mild diuretic effect. To offset that effect, drink an extra 100 ml of water for every cup of coffee or strong tea you consume.

How much water should I drink to lose weight?

Drinking water supports weight loss by briefly boosting metabolism, suppressing appetite, and replacing high-calorie drinks. Add 250–500 ml above your base requirement when actively trying to lose weight.

How does exercise affect water needs?

For every hour of moderate exercise, you need an extra 400–700 ml of water. Intense training or exercising in heat can require 700–1,000 ml extra per hour.

How much water do pregnant or breastfeeding women need?

Pregnant women are recommended to drink about 2.3 liters (roughly 10 cups) per day. Breastfeeding women need an additional 500 ml (about 2 cups) per day to replace fluids used in milk production.

What does urine color indicate about hydration?

Pale yellow means well hydrated (ideal); dark yellow means you should drink water soon; amber or brown signals significant dehydration. Colorless can indicate overhydration.

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