Water Intake Calculator
Estimate how much water to drink per day from your weight. Base formula is weight (kg) × 0.033. You can add extra for hot weather or high activity (about 10–20% each).
FAQ
- Why weight in kilograms?
- The guideline is often given as about 33 ml per kg of body weight per day. Convert pounds to kg by dividing by 2.205.
- When should I add the heat or activity extra?
- Add 10–20% for hot climates or heavy sweating, and 10–20% if you exercise a lot or have a physical job. You can combine both.
- Does this include water from food?
- This is a total fluid guideline. Part of it can come from food (soups, fruit, etc.). Not all has to be plain water.
- Is more water always better?
- No. Drinking far beyond need has no proven benefit and can be harmful in rare cases. Use this as a reasonable target, not a minimum to exceed at all costs.
How Much Water Should I Drink?
Daily water intake is often estimated from body weight. A common rule is weight in kilograms times about 0.033, which gives liters per day. For example, 70 kg × 0.033 ≈ 2.3 liters. That’s a starting point for moderate conditions.
You may need more in the heat or when you’re very active. Adding 10–20% for heat and 10–20% for high activity is a simple way to adjust. Thirst, urine color, and how you feel are also useful signals — drink when thirsty and aim for pale yellow urine.
Health calculators like this give general guidance only. They don’t replace medical advice. People with certain heart or kidney conditions may need to limit fluid; when in doubt, ask your doctor.
Also try our Protein Intake Calculator or Calorie Deficit Calculator.
People Also Ask
- How much water should I drink per day?
- How do I convert water intake to liters by weight?
- Should I drink more water when exercising?
- Does water from food count toward daily intake?
Last updated: February 2026