500
mg
140
mg
35
mg
18
g
500
mg
140
mg
35
mg
18
g
7.1
mg/kg
500
mg
140
mg
35
mg
18
g
500
mg
140
mg
35
mg
18
g
7.1
mg/kg
Electrolytes are electrically charged minerals that regulate critical physiological processes in the human body, including fluid balance, nerve signal transmission, muscle contraction and relaxation, and acid-base homeostasis. The primary electrolytes of concern for hydration are sodium, potassium, magnesium, and chloride, each playing a distinct and irreplaceable role in maintaining cellular function.
The Electrolyte Drink Calculator helps you formulate a custom electrolyte beverage tailored to your specific activity level, sweat profile, and batch size. Rather than relying on commercial products with fixed formulations, this calculator allows you to understand the electrolyte concentrations appropriate for your situation and prepare a drink that meets your individual needs.
Sodium is the dominant extracellular electrolyte and the most important component of any rehydration formula. It drives thirst, retains fluid in the bloodstream, and is lost at concentrations of approximately 400 to 1,100 mg per liter of sweat, depending on individual genetics, fitness level, acclimatization, and sweat rate. Consuming adequate sodium during and after fluid loss prevents the dangerous dilution of blood sodium known as hyponatremia.
Potassium is the primary intracellular electrolyte and is lost in sweat at roughly one-third the rate of sodium. It is essential for normal cardiac rhythm, skeletal muscle function, and glycogen synthesis in muscle and liver cells. Most healthy diets provide adequate potassium for recovery, but endurance athletes and individuals with significant fluid losses benefit from including it in hydration formulas.
Magnesium plays roles in over 300 enzymatic reactions, including ATP synthesis and protein metabolism. While sweat losses of magnesium are relatively small compared to sodium and potassium, deficiency is common in athletes due to inadequate dietary intake and increased urinary losses associated with high training loads.
A small amount of sugar — typically 5 to 8 grams per 100 mL (5 to 8% concentration) — facilitates sodium absorption in the small intestine via sodium-glucose co-transport. This mechanism, which is the basis of oral rehydration therapy used worldwide, significantly enhances the rate of fluid absorption compared to plain water alone.
This calculator provides per-liter targets and scales them to your desired batch size, giving you precise quantities for each ingredient when making a homemade electrolyte drink.
The formulas are as follows:
Sodium per liter = Base sodium (mg/L) × Sweat multiplier — Base values by activity: Rest/Illness 400, Mild Exercise 300, Moderate Exercise 500, Endurance 700, Heat Exposure 600 mg/L. Sweat multipliers: Light 0.8×, Moderate 1.0×, Heavy 1.4×.
Potassium per liter = Sodium per liter × 0.35
Magnesium per liter = 30 mg (constant, based on average sweat loss)
Sugar per liter = 10g (rest/illness) or 30g (exercise) to support co-transporter absorption
All values are scaled by batch size (liters) for total batch quantities.
For rest and illness scenarios (such as recovery from vomiting or diarrhea), the formula closely mirrors WHO oral rehydration solution standards. For endurance activities or heavy sweaters, sodium targets above 700 mg/L represent a high-electrolyte formulation appropriate for severe sweat losses. If sodium per liter exceeds 1000 mg, the drink may taste uncomfortably salty — reducing sugar or using a fruit juice base can mask the saltiness while maintaining efficacy.
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A heavy-sweating endurance athlete requires a high-sodium formulation of 980 mg/L — approximately double the sodium in a standard commercial sports drink.
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For mild illness recovery, a gentle formula of 400 mg sodium/L with minimal sugar closely matches WHO oral rehydration salt guidelines for mild dehydration.
All sports drinks contain electrolytes, but not all electrolyte drinks are sports drinks. Electrolyte formulas designed for illness recovery or everyday hydration typically have lower sugar content and are not optimized for performance energy delivery. Sports drinks balance fluid, electrolytes, and carbohydrates specifically for athletic performance contexts.
Yes, table salt (sodium chloride) is the most common sodium source for homemade electrolyte drinks. Note that 1 gram of table salt contains approximately 390 mg of sodium and 610 mg of chloride. Use a kitchen scale for accuracy. Pink Himalayan salt and sea salt are nutritionally equivalent to table salt for this purpose.
Potassium chloride (sold as salt substitute or NoSalt) is the most convenient way to add potassium to homemade electrolyte drinks. Alternatively, coconut water or orange juice as a drink base naturally provides potassium. Cream of tartar (potassium bitartrate) is another option used by some recipe creators.
For everyday use and short-duration exercise, magnesium in drinks is not critical. However, for endurance athletes, frequent sauna users, and people on diets low in nuts, seeds, and leafy greens, supplemental magnesium can help prevent muscle cramps, improve sleep quality, and support energy metabolism.
Small amounts of glucose enhance sodium absorption in the small intestine via the sodium-glucose co-transporter (SGLT1). This mechanism can double or triple the rate of fluid and electrolyte absorption compared to electrolyte solutions without sugar. Even a 2 to 5% glucose concentration is sufficient to activate this pathway.
Yes. Excessive sodium intake can cause hypernatremia in severe cases. Excessive potassium can impair cardiac rhythm if kidney function is compromised. For healthy individuals, the quantities in this calculator are well within safe ranges. Those with kidney disease, hypertension, or heart conditions should consult a physician before using high-electrolyte formulas.
WHO ORS contains approximately 90 mEq/L sodium (about 2,070 mg/L), which is much higher than sports drinks (400-700 mg/L). WHO ORS is designed for severe dehydration from diarrheal illness, not exercise. A modified low-osmolarity ORS (75 mEq/L sodium) is now recommended for children, while sports drinks are better suited for exercise hydration.
Common causes include excessive sweating, vomiting, diarrhea, inadequate dietary intake, certain medications (especially diuretics), overdrinking plain water, kidney disorders, and endocrine conditions affecting aldosterone levels. Athletes are at increased risk due to high fluid and electrolyte turnover.
Yes, electrolyte tablets are a convenient and precise way to add electrolytes to water. Most contain 200 to 500 mg sodium, 100 to 200 mg potassium, and various other minerals per tablet. They are particularly useful for travel and racing when carrying loose ingredients is impractical.
Symptoms of electrolyte depletion include muscle cramps, fatigue, dizziness, headache, nausea, and in severe cases, confusion and irregular heartbeat. Salty white residue on skin or clothing after exercise is a sign of high sodium sweat losses. Blood tests (basic metabolic panel) can accurately diagnose electrolyte imbalances.
Roboculator Team
The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
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