Hydration Basics: How Much Water Do You Really Need?

There isn’t a single magic number. A practical baseline is 35 mL per kilogram of body weight, then adjust for exercise, climate, and life stage. The calculator on the home page does the math for you and gives cup/bottle equivalents.

Start with body weight

Your tissues, blood, and cells rely on water. Weight provides a useful proxy for total body water needs. At 70 kg, the baseline is ~2.45 L/day before adjustments.

Add exercise

For moderate to vigorous activity, add about 12 mL per exercise minute. Long, hot sessions may need more, especially if your sweat rate is high.

Consider climate & life stage

Hot and humid conditions increase sweat and fluid needs. Pregnancy often requires roughly +0.3 L/day; breastfeeding +0.7 L/day.

Use simple feedback

• Thirst typically works, sip regularly across the day.
• Urine color: aim for pale straw.
• Heavier exercise or heat means you should increase intake.

Educational content only; not medical advice.