Water Intake Calculator
Estimate daily hydration needs from body weight and activity.
Enter your details and calculate.
Legion Electrolytes
Water alone is half of it. Sweat takes sodium, potassium and magnesium with it, and replacing the water without them is what leaves people flat after long or hot sessions.
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Water is half of it. Sodium is the other half
The printable protein chart, plus the electrolyte guidance plain water does not cover.
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FAQs
How much water do I really need per day?
Needs scale with bodyweight, activity, sweat rate and climate — which is why a single universal number doesn't work. Beyond the calculator's estimate, two practical checks work well: drink to thirst, and aim for pale-yellow urine most of the day.
Does coffee count toward my daily fluid intake?
Yes. Caffeinated drinks have a mild diuretic effect, but the fluid they deliver outweighs it — net hydration is positive. Coffee, tea and food moisture all count toward daily intake.
When do I need electrolytes instead of just water?
For most workouts under an hour, water is enough. For long, hot or very sweaty sessions (60–90+ minutes), replacing sodium becomes important — see our electrolytes guide for evidence-based options.