Electrolyte Calculator
Estimate the sodium, potassium, magnesium and calcium you'll lose in a workout — and see which bottled mineral waters replace them best.
How we estimate the numbers
Sweat rate ranges follow ACSM and Gatorade Sports Science Institute guidance: light ~0.5 L/h, moderate ~1.0 L/h, heavy ~1.6 L/h. Hot or humid environments add ~25%.
Sweat sodium varies a lot between individuals (200–2000 mg/L). We use 700/1000/1500 mg/L for light/moderate/heavy. Potassium ~200 mg/L, magnesium ~10 mg/L and calcium ~20 mg/L are typical mid-range values. Keto increases sodium needs ~30%; fasting modestly increases both sodium and potassium turnover.
Educational only — not medical advice. Talk to your doctor for personalised guidance.
