Hydration Electrolyte Mix Calculator

Calculate the precise amounts of sodium, potassium, and magnesium to add to water for a custom hydration drink. Supports metric (mg/L, mmol/L) and US units. All calculations run instantly and offline in your browser.

Educational only, not medical advice.

Mix Formula

Concentration Units:

Water Volume (Liters)

Example: 0.5, 1, 2.5 (supports both . and , as decimal)

Sodium Target

Typical: 400–1000 mg/L

Potassium Target

Typical: 100–300 mg/L

Magnesium Target

Typical: 10–100 mg/L

Results

Enter your targets and click "Calculate Mix"

Interpretation Guide

Low intensity: Sodium < 500 mg/L, Potassium < 150 mg/L

Moderate activity: Sodium 500–800 mg/L, Potassium 150–250 mg/L

High sweat loss: Sodium > 800 mg/L, Potassium > 250 mg/L (use with caution)

Why Electrolyte Balance Matters

Proper hydration isn't just about water—it's about maintaining the right balance of electrolytes lost through sweat, especially sodium, potassium, and magnesium. A balanced DIY electrolyte drink can support hydration during exercise, heat exposure, or illness, and may help avoid muscle cramps and fatigue.

How to Use This Calculator

Enter the total volume of water you want to fortify (e.g., 1 liter for a standard bottle).
Set your desired concentration for each electrolyte. Use the unit toggle to switch between mg/L (common for supplements) and mmol/L (used in clinical settings).
Click "Calculate Mix" to see how much of each electrolyte compound to add.
Use the "Copy Results" button to save your recipe.

Example Mixes

Use Case	Water	Sodium (mg/L)	Potassium (mg/L)	Magnesium (mg/L)
Light daily hydration	1 L	300	100	20
Moderate workout (1 hour)	0.75 L	600	200	40
High-intensity sweat replacement	1.5 L	800	250	60

Common Electrolyte Sources

Mineral	Common Compound	Elemental Content	Notes
Sodium	Table salt (NaCl)	~393 mg Na per 1 g salt	Iodized or sea salt works
Potassium	Potassium chloride (KCl)	~524 mg K per 1 g KCl	Bitter taste; use sparingly
Magnesium	Magnesium citrate	~161 mg Mg per 1 g citrate	Well‑absorbed, mild laxative effect

Activity Adjuster

See how your electrolyte needs change with estimated sweat loss.

Estimated Sweat Rate: Moderate ~500 mL/hour

Light Moderate Heavy Very Heavy Athlete

Frequently Asked Questions

How accurate are these calculations?

The calculations are mathematically precise for the given inputs, but real‑world absorption, individual sweat composition, and product purity can vary. Use as a starting point and adjust based on personal experience.

Can I use this if I have kidney or heart issues?

No. If you have kidney disease, heart failure, hypertension, or are on medications that affect electrolytes (like diuretics), you must consult a doctor or dietitian before altering your electrolyte intake. This tool is not safe for medically restricted diets.

Why does the calculator show amounts in grams?

Grams are the most precise unit for weighing powders. Use a digital kitchen scale (0.1‑g resolution) for accuracy. Volumetric measures (teaspoons) are less reliable due to density variations.

When should I seek professional help?

If you experience dizziness, confusion, irregular heartbeat, severe muscle weakness, or extreme thirst after electrolyte use, stop immediately and seek medical attention. These can signal electrolyte imbalance.

Formulas & Assumptions

Basic formula: Amount (g) = (Target concentration × Water volume) / (Elemental content in compound).
Unit conversions: 1 mmol/L Na = 22.9898 mg/L; 1 mmol/L K = 39.0983 mg/L; 1 mmol/L Mg = 24.305 mg/L.
Elemental content assumptions: NaCl: 39.33% Na by weight; KCl: 52.45% K; Magnesium citrate: 16.1% Mg.
Rounding: Results rounded to 2 decimal places for grams, 1 decimal for milligrams.
This tool assumes pure compounds; actual supplement purity may vary.

For informational and educational purposes only. Estimates depend on your inputs and simplifying assumptions. This tool is not medical advice and does not diagnose or treat any condition. If you have symptoms, abnormal readings, or urgent concerns, contact a qualified healthcare professional.

References & Further Reading

Common unit conversions and measurement best practices; Typical wellness metric ranges and public health guidance concepts; General nutrition and hydration guidance concepts; Basic exercise physiology concepts for sweat electrolyte composition.

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Hydration Electrolyte Mix Calculator

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