mEq to mg Calculator

Convert milliequivalents (mEq) to milligrams (mg) using molar mass and valence. Essential tool for medical professionals, pharmacists, and chemistry students.

Medical Chemistry Tool:

Convert between chemical activity (mEq) and weight (mg) measurements for accurate medical dosing and laboratory calculations.

Medical Unit Converter

Conversion Direction

Enter milliequivalents or milligrams

Sodium (Na⁺): Molar mass: 23 g/mol, Valence: 1

Auto-filled for presets, manual for custom substances

Auto-filled for presets, manual for custom substances

Conversion Results

Enter values and click "Convert"

mEq and mg Conversions in Medicine

Milliequivalents (mEq) and milligrams (mg) are both used in medicine and chemistry, but they measure different things. While milligrams represent weight, milliequivalents account for a substance's chemical activity and electrical charge.

This distinction is crucial in medical calculations because two substances with the same weight can behave very differently in the body. The key factor is valence, which represents the electrical charge of an ion.

The Mathematical Relationship

The calculator uses medically accepted formulas for accurate conversions:

mEq to mg Formula:
mg = (mEq × Molar Mass) ÷ Valence
mg to mEq Formula:
mEq = (mg × Valence) ÷ Molar Mass

These formulas ensure accurate results for both monovalent and multivalent ions.

Practical Examples

Here are common conversions for medical electrolytes:

Substance mEq Molar Mass Valence Result (mg)
Sodium (Na⁺) 10 23 1 230 mg
Potassium (K⁺) 5 39 1 195 mg
Calcium (Ca²⁺) 4 40 2 80 mg
Magnesium (Mg²⁺) 6 24.3 2 72.9 mg
Chloride (Cl⁻) 8 35.5 1 284 mg
Sodium (Na⁺) 20 23 1 460 mg
Potassium (K⁺) 10 39 1 390 mg
Calcium (Ca²⁺) 8 40 2 160 mg
Magnesium (Mg²⁺) 12 24.3 2 145.8 mg
Sodium (Na⁺) 15 23 1 345 mg
Potassium (K⁺) 7.5 39 1 292.5 mg
Calcium (Ca²⁺) 6 40 2 120 mg
Magnesium (Mg²⁺) 8 24.3 2 97.2 mg
Chloride (Cl⁻) 12 35.5 1 426 mg
Sodium (Na⁺) 25 23 1 575 mg
Potassium (K⁺) 15 39 1 585 mg
Calcium (Ca²⁺) 10 40 2 200 mg
Magnesium (Mg²⁺) 15 24.3 2 181.5 mg
Chloride (Cl⁻) 18 35.5 1 639 mg
Sodium (Na⁺) 30 23 1 690 mg
Potassium (K⁺) 20 39 1 780 mg
Calcium (Ca²⁺) 12 40 2 240 mg
Magnesium (Mg²⁺) 18 24.3 2 218.7 mg
Chloride (Cl⁻) 25 35.5 1 887.5 mg
Sodium (Na⁺) 2 23 1 46 mg
Potassium (K⁺) 1 39 1 39 mg
Clinical Tip:

When working with electrolytes, remember that the valence affects bioavailability. Calcium ions (Ca²⁺) with valence 2 require twice the milliequivalents compared to monovalent ions for the same chemical effect.