Electrolyte Calculator

Electrolytes are most important before, during, and after exercise lasting more than 45–60 minutes. For shorter workouts, water alone is usually sufficient. In hot climates or during high-intensity sessions, starting electrolyte intake early in your workout helps prevent cramping and dehydration.

Weigh yourself (in kg) before and after a 60-minute workout without drinking fluids. Every 1 kg lost equals approximately 1 litre of sweat. This calculator estimates your sweat rate based on your body weight, exercise intensity, duration, and climate.

Sodium is the primary electrolyte lost in sweat and it regulates fluid balance inside and outside your cells. Drinking plain water without replacing sodium can actually dilute blood sodium levels — a condition called hyponatremia — which can cause nausea, headaches, or in severe cases, serious health issues.

Sweat contains primarily sodium (the most abundant), along with potassium, magnesium, calcium, and chloride. The amounts lost vary by individual, intensity, and environment. Sodium and potassium are typically the most critical to replace after intense exercise.

Higher-intensity exercise like HIIT or endurance training dramatically increases sweat rate — often 1–2 litres per hour compared to 0.3–0.5 litres during light activity. This means proportionally more sodium, potassium, and magnesium are lost and need to be replaced to maintain performance and avoid muscle cramps.

Yes, significantly. In hot or humid conditions, your body sweats more to cool itself, which accelerates electrolyte losses. Athletes training in temperatures above 25°C (77°F) may need 50–100% more electrolyte replacement than those exercising in cooler environments.

Use this calculator daily or before key training sessions to plan your hydration strategy. On rest days, your fluid and electrolyte needs drop considerably, so adjust accordingly. For multi-day events or back-to-back training sessions, consistent electrolyte replenishment between sessions is especially important for recovery.

For light or moderate exercisers, a balanced diet with foods like bananas, leafy greens, nuts, and lightly salted meals can cover most electrolyte needs. However, during intense or prolonged exercise lasting over 90 minutes — especially in heat — dedicated electrolyte drinks or supplements are generally more practical and reliable.