Advanced Water Intake Calculator

General rule: 35ml per kg of body weight. A 70 kg person needs ~2.5L/day. However, this varies based on activity, climate, and health. Our calculator adjusts for all these factors. Minimum: 30ml/kg. Maximum safe: 45ml/kg in normal conditions.

Activity increases water loss through sweat. Sedentary: baseline needs. Light activity: +15%. Moderate (30-60 min exercise): +30%. Very active (1-2 hours): +50%. Athletes: +70%. Additionally, add 500ml per 30 minutes of exercise.

Hot/humid climates increase sweating: +25% water needs. Very hot (>35°C): +50%. Cold/dry air: +10% (dry air increases respiration losses). High altitude (>2500m): +20% (faster breathing, lower humidity). Our calculator includes all these adjustments.

Pregnant women need ~300ml extra daily to support increased blood volume and amniotic fluid. Breastfeeding women need ~700ml extra to produce breast milk. These are in addition to normal hydration needs based on weight.

Yes, but with reduced hydration effect. Coffee: ~80% hydrating (caffeine is mild diuretic). Tea: ~95% hydrating. For every cup of coffee, you can count ~200ml toward hydration. However, water is still the best choice for pure hydration.

Mild (1-2% loss): Thirst, dry mouth, dark urine, headache. Moderate (3-5%): Fatigue, dizziness, reduced urination, dry skin, muscle cramps. Severe (>5%): Rapid heartbeat, confusion, no urination, sunken eyes, fainting. Seek help for severe symptoms.

Best indicator: Urine color. Pale yellow = well hydrated. Clear = possibly over-hydrated. Dark yellow/amber = dehydrated. Other signs of good hydration: Regular urination (6-8 times/day), no persistent thirst, skin elasticity returns quickly when pinched.

Yes. Overhydration (hyponatremia) occurs when you drink so much that sodium levels drop dangerously. Symptoms: Nausea, headache, confusion, seizures. Safe limit: ~45ml/kg/day or 1L/hour maximum. Athletes in long events are at highest risk. Spread intake throughout the day.

About 20% of daily water intake comes from food. Water-rich foods: Watermelon (92%), cucumber (96%), lettuce (96%), tomatoes (94%), oranges (87%), yogurt (85%). A balanced diet contributes ~400-500ml of water daily.

Optimal timing: Morning (2 glasses after waking), 30 min before meals (aids digestion), during meals (moderate), between meals, before/during/after exercise. Avoid large amounts right before bed (disrupts sleep). Space intake evenly throughout waking hours.

Illness increases water needs significantly. Fever: +500ml (sweating). Vomiting/diarrhea: Replace lost fluids (can be 2-3L extra). Cold/flu: +300-500ml (mucus production). Oral rehydration solutions may be needed for severe fluid loss.

Both are equally hydrating. Cold water: May feel more refreshing, minor calorie burn to warm it up. Room temperature: Easier on some stomachs, traditional Chinese medicine recommends this. For exercise: Cold water may be absorbed slightly faster. Choose based on preference.

Alcohol is DEHYDRATING. It blocks ADH hormone, making you urinate more than you drink. For every alcoholic drink, you may lose 250-350ml extra fluid. This is why hangovers cause headache/thirst. Counter with: 1 glass of water per alcoholic drink.

Older adults may have reduced thirst sensation, but water needs remain similar. Risk of dehydration actually increases with age. Kidney function changes and medications (diuretics) can affect needs. Elderly should consciously drink water even without feeling thirsty.

Methods: Use our built-in tracker (click + for each glass). Keep a marked water bottle. Set hourly reminders. Use habit-tracking apps. Target: Drink 1 glass (250ml) every 1-2 hours during waking hours. By bedtime, you should hit your daily goal.