Free online calculator
Water Intake Calculator
Estimate daily water intake target from body weight and activity level.
Quick Answer
How It Works
Baseline intake is calculated per kilogram of body weight, then adjusted by activity multiplier.
- Enter body weight.
- Choose activity level.
- Read estimated daily water target.
Examples use USD-style formatting. Tax rates, fees, and legal rules vary by country and change over time — treat results as estimates and confirm important numbers with a qualified professional.
Interactive Calculator
Estimated daily intake: 2.45 L
Example Use Case
More active users get higher hydration estimates than sedentary users at same weight.
Detailed Guide
Hydration targets are useful baselines for routine planning and consistency.
Real needs vary with climate, activity, and individual health context.
This calculator supports daily awareness but should not override clinical recommendations.
Track response over time and adjust pragmatically instead of forcing static intake rules.
Assumptions and Limits
Guidance is general and not medical advice for kidney, heart, or endocrine conditions.
Common Mistakes to Avoid
- Ignoring climate and sweat-loss differences.
- Treating estimate as strict requirement.
- Forgetting fluid intake from foods and beverages.
FAQ
Can I use this calculator for free?
Yes. This tool is free and designed for practical day-to-day decisions.
Why might results differ from another website?
Differences usually come from rounding rules, assumptions, or region-specific formulas.
Is this suitable for legal or financial advice?
No. Treat outputs as guidance and validate with qualified professionals for final decisions.
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How we choose formulas and check results: Methodology · Last reviewed 2026-07-25