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Free Science-Based Tools

Electrolyte & Hydration Calculators

Personalized, science-backed calculators using WHO, NIH, and IOM guidelines. Free, no signup required — get your exact daily electrolyte and hydration needs in seconds.

Why These Calculators Are Different

Science-Based, Not Generic

Our algorithms use WHO, NIH, and IOM guidelines with peer-reviewed adjustment factors. Most online calculators use oversimplified "weight × constant" formulas that ignore diet type, climate, and activity intensity.

Keto & Fasting Specific

Standard calculators don't account for keto flu prevention (2,000+mg extra sodium) or fasting electrolyte depletion. Our diet-specific adjustments use research from Volek & Phinney on ketogenic mineral needs.

Product Recommendations

Based on your calculated needs, we recommend the best electrolyte product for your specific profile — keto dieters get LMNT recommendations, fasters get Dr. Berg's, athletes get performance-specific picks.

Electrolyte-Water Balance

Our hydration calculator doesn't just tell you how much water to drink — it tells you how to balance water with electrolytes to prevent hyponatremia, a dangerous condition caused by drinking too much plain water.