Water Intake Calculator
How it worksA simple daily hydration guideline from body weight
Your details
Using: 70.0 kg
Daily water guideline
Target (approx.)
2,450 ml / day
≈ 10.4 US cups (8 fl oz)
Visual target
10.4cups
Illustrated against a 4 L scale so you can picture the volume. Adjust up in heat or long sessions.
About this tool
Hydration supports temperature regulation, digestion, and training feel. Needs vary with climate, sweat rate, diet (water-rich foods), and caffeine or alcohol intake.
A common heuristic is about 35 ml of fluid per kilogram of body weight per day. That is a starting point — not a hard medical rule.
Pale-straw urine (when not influenced by vitamins) and how you feel in workouts are often better day-to-day signals than any single calculator.
How it works
- Enter your weight in Your details.
- We multiply by ~35 ml/kg and show ml/day plus an approximate US cup conversion.
- Increase toward the higher end on hot days, long cardio, or heavy sweating; ease off if your clinician has fluid limits.
Practical tips
- Sip across the day rather than chugging large volumes at once.
- Include water from food (fruit, soups) when thinking about total fluids.
- Electrolytes may matter more than plain water volume in very long or salty sweat sessions.
Frequently asked questions
Does coffee count toward water intake?
Moderate coffee and tea still contribute fluid for most people. Extremely high caffeine intake can have other effects — balance with water-rich habits.
Can I drink too much water?
Yes. Overhydration is uncommon but real. People with heart, kidney, or endocrine conditions should follow medical fluid advice.
Is 8 glasses still the rule?
Eight cups is a memorable slogan, not personalised science. Body size and climate change needs — hence the weight-based starting estimate.
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Disclaimer: These tools provide general estimates only. They are not medical advice. For health conditions, pregnancy, or personalised nutrition, speak with a qualified professional.