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Water Intake Calculator

Estimate a practical daily hydration target from body weight, activity time, and climate.

Interactive calculator

Estimate daily water intake

Use body weight, activity, and climate to set a practical daily hydration target in liters and glasses.

Results

Daily water target

3.33 L

Glasses

13.3

Based on 250 mL glasses

500 mL bottles

6.7

How to use it

  1. 01Enter body weight in kilograms.
  2. 02Add the minutes of exercise or heavy activity in a typical day.
  3. 03Choose the climate level to adjust for temperature and sweating conditions.

Result guide

  • The liters result is the clearest planning number for most people.
  • Glass and bottle counts help turn the target into something easier to follow during the day.
  • Hydration needs can still change with illness, heat exposure, and medical advice.

About this calculator

Water intake tools get repeated use because hydration targets are easy to understand but still benefit from a quick personalized estimate.

The calculator is intentionally simple. It gives a planning baseline, not a medical prescription for every health condition.

Frequently asked questions

Is this target exact for every person?

No. It is a practical estimate, and real needs can vary with diet, weather, medication, and medical conditions.

Why does activity raise the water target?

More movement usually means more sweat loss and a higher need to replace fluids.

Can this be used with hot-weather training?

Yes, but treat it as a baseline rather than a full heat-management protocol.

DE
Per WHO guidelines / Peer-reviewed researchFormula version: 2026

Reviewed by Dr. Elena Rostova, MD, PhD

Medical Doctor & Clinical Nutrition Researcher

Reviews health index calculators, unit converter benchmarks, and mathematical models against WHO guidelines and peer-reviewed research.

Formula last verified: June 2026

Sources: Per WHO guidelines / Peer-reviewed research/WHO BMI classification guidance/Published TDEE and basal metabolic rate formula references

Disclaimer: Calculator results are for general reference and educational purposes only per WHO standards. Health indexes and mathematical models are not a substitute for professional medical diagnosis, clinical nutrition, or certified trade advice.

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