How much water should I drink per day?

The general guideline is 35ml per kg of body weight (about half your body weight in ounces). However, this varies based on activity level, climate, and individual factors. Listen to your body and drink when thirsty.

Can I drink too much water?

Yes, overhydration (hyponatremia) can occur but is rare. Symptoms include nausea, headache, and confusion. For most people, drinking 3-4 liters per day is safe. Athletes may need more but should consult professionals.

Does coffee or tea count towards water intake?

Yes! While caffeine has a mild diuretic effect, coffee and tea still contribute to hydration. The water content outweighs the diuretic effect. However, water remains the best choice.

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Water Intake Calculator

Calculate daily water intake needs based on body weight and activity level with health targets. Features hydration recommendations including climate adjustments, exercise intensity factors, pregnancy and breastfeeding modifications, and daily ounces targets for optimal health.

How to Use the Water Intake Calculator

Use the Water Intake Calculator to daily water intake needs based on body weight and activity level with health targets. Features hydration recommendations including climate adjustments, exercise intensity factors, pregnancy and breastfeeding modifications, and daily ounces targets for optimal health.. Enter your values to get accurate, instant results tailored to your situation.

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Complete Hydration Guide

Optimize water intake for health and performance

Expert Tips

Hydration Timing: Drink 500mL upon waking to rehydrate after 7-8 hours without fluids. Spread intake throughout day - don't chug large amounts at once for better absorption.
Exercise Hydration: Pre-exercise: 500mL 2 hours before. During: 200-300mL every 15-20 min. Post: 150% of fluid lost (weigh before/after to measure sweat loss).
Dehydration Signs: Dark yellow urine, dry mouth, fatigue, headache, dizziness. Urine should be pale yellow. Clear = overhydrated, dark = dehydrated. Monitor color.
Electrolyte Balance: Plain water fine for <1 hour exercise. Longer or intense: add electrolytes (sodium, potassium). Prevents hyponatremia (dangerous over-hydration).

Hydration Fundamentals — Why water intake matters

Water Functions in Body

Temperature Regulation: Sweating cools body. Dehydration reduces sweating capacity, increases core temperature, impairs performance.
Nutrient Transport: Blood is 90% water. Carries oxygen, nutrients to cells. Removes waste products. Dehydration thickens blood.
Joint Lubrication: Synovial fluid cushions joints. Dehydration reduces cushioning, increases injury risk, joint pain.
Cognitive Function: Brain is 75% water. 1-2% dehydration impairs focus, memory, mood. Headaches common.

Individual Needs Vary

Body Weight: Larger people need more water. 35mL/kg standard, but activity level, climate, health status all modify needs.
Climate Impact: Hot/humid: +500-1000mL. Altitude: +500-1000mL. Cold/dry: +250-500mL. Adjust baseline for environment.
Activity Level: Sedentary: baseline. Moderate: +500-1000mL. Active: +1000-1500mL. Very active: +1500-2500mL daily.
Health Conditions: Kidney stones, UTIs: increase intake. Heart failure, kidney disease: may need restriction. Consult doctor.

Hydration Strategies — Practical tips for optimal hydration

Daily Hydration Schedule

Morning (500mL): Upon waking, before breakfast. Rehydrates after 7-8 hours sleep. Jumpstarts metabolism.
Mid-Morning (250-500mL): Between breakfast and lunch. Maintains hydration through morning activities and work.
Lunch (250mL): With meal. Aids digestion. Don't drink too much during meals - can dilute digestive enzymes.
Afternoon (500mL): Between lunch and dinner. Prevents afternoon energy slump. Especially important if exercising after work.
Pre-Dinner (250mL): Before evening meal. Helps with portion control - thirst often confused with hunger.
Evening (250-500mL): After dinner but 1-2 hours before bed. Avoid drinking too close to bedtime (frequent urination disrupts sleep).

Exercise Hydration Protocol

Pre-Exercise (2-4 hours before): 400-600mL to start hydrated. Allows time for absorption and urination before workout.
During Exercise (<1 hour): Water sufficient. 200-300mL every 15-20 min. Mouth rinse OK for very short workouts.
During Exercise (>1 hour): Sports drink with electrolytes. 30-60g carbs/hour for energy. Sodium prevents hyponatremia.
Post-Exercise: 150% of weight lost. Example: lost 1kg (1L sweat) = drink 1.5L over 2-4 hours. Includes food water content.

Frequently Asked Questions

How much water should I drink per day?: The general guideline is 35ml per kg of body weight (about half your body weight in ounces). However, this varies based on activity level, climate, and individual factors. Listen to your body and drink when thirsty.
Can I drink too much water?: Yes, overhydration (hyponatremia) can occur but is rare. Symptoms include nausea, headache, and confusion. For most people, drinking 3-4 liters per day is safe. Athletes may need more but should consult professionals.
Does coffee or tea count towards water intake?: Yes! While caffeine has a mild diuretic effect, coffee and tea still contribute to hydration. The water content outweighs the diuretic effect. However, water remains the best choice.