Water Intake Calculator

How Much Water Do You Really Need?

There's no universal number. Your hydration need depends on body weight, activity level, climate, and individual factors. This calculator uses a base of 35ml per kg of body weight, then adds extra for exercise days.

Factors That Increase Your Needs

Factor	Extra Water Needed
Each workout session	+350–700ml (12–24 oz)
Hot or humid weather	+500–1000ml
High altitude (>5000ft)	+500ml
Pregnancy	+300ml
Breastfeeding	+700ml
Fever, illness, or vomiting	Replace lost fluids + extra

Spot Dehydration Early

• Urine color: Pale yellow = good. Dark yellow = drink more. Clear = maybe overhydrating.
• Thirst: By the time you feel thirsty, you're already mildly dehydrated.
• Headache: Often a sign of dehydration. Water first, then consider pain relief.
• Fatigue: Low energy? Try a glass of water before caffeine.

Easy Hydration Habits

• Start every morning with a full glass of water
• Keep a water bottle at your desk
• Drink a glass before each meal
• Set phone reminders if you forget
• Eat water-rich foods: cucumber, watermelon, strawberries, oranges, lettuce

About 20% of your water intake comes from food, so eating water-rich foods counts.

Can You Drink Too Much?

Yes, though it's rare. Hyponatremia (dangerously low sodium) can occur in endurance athletes who drink excessive amounts without replacing electrolytes. For most people, drinking when thirsty and a bit more during exercise is perfectly safe.