meq/l to mmol/l Converter

By: Patrick Myers Patrick Myers is the CEO and Founder of Calculator Academy. He has over eight years of experience developing online calculators and holds a B.S. in Mechanical Engineering. His work focuses on formula implementation, calculator accuracy, unit conversions, and creating practical tools that are easy to use.

Last Updated: December 11, 2025

meq/l to mmol/l converter

Convert mEq/L to mmol/L or mmol/L to mEq/L for sodium, potassium, chloride, bicarbonate, calcium, magnesium, and phosphate ions.

mEq/L → mmol/L
mmol/L → mEq/L
▸ How this is calculated
Copy result

Quick overview: mEq/L to mmol/L

The relationship between mEq/L and mmol/L depends on the ion’s absolute charge (|z|): mmol/L = mEq/L ÷ |z|.

  • For Na⁺, K⁺, Cl⁻ (|z| = 1): 10 mEq/L = 10 mmol/L
  • For HCO₃⁻ (|z| = 1): 24 mEq/L = 24 mmol/L
  • For Ca²⁺, Mg²⁺ (|z| = 2): 10 mEq/L = 5 mmol/L
  • For PO₄³⁻ (|z| = 3): 9 mEq/L = 3 mmol/L

The converter applies this rule automatically once you enter the value in mEq/L and choose the corresponding ion or electrolyte.

This page explains how to convert milliequivalents per liter (mEq/L) to millimoles per liter (mmol/L) for common clinical ions. For monovalent ions like sodium (Na⁺) or potassium (K⁺), the numeric values in mEq/L and mmol/L are the same. For divalent ions such as calcium (Ca²⁺) or magnesium (Mg²⁺), you divide the mEq/L value by 2 to obtain mmol/L.

mEq/L to mmol/L Formula

mEq/L is a concentration measure that incorporates both the amount of substance and its electrical charge. mmol/L is a more purely chemical measure that reflects the number of particles regardless of charge. The two are linked through the ion’s valence (absolute charge, |z|) using:

  • mEq/L = mmol/L × |z|
  • mmol/L = mEq/L ÷ |z|

Here, |z| is the absolute value of the ion’s charge. Some common examples:

  • Na⁺, K⁺, Cl⁻, HCO₃⁻: |z| = 1
  • Ca²⁺, Mg²⁺: |z| = 2
  • PO₄³⁻: |z| = 3

Once you know the charge, the conversion is straightforward. For example, 10 mEq/L of Ca²⁺ corresponds to 10 ÷ 2 = 5 mmol/L, while 10 mEq/L of Na⁺ corresponds to 10 ÷ 1 = 10 mmol/L.

mEq/L to mmol/L conversion table

The table below shows example conversions for a 10 mEq/L concentration of several common ions using the relationship mmol/L = mEq/L ÷ |z|.

Ion Typical |z| 10 mEq/L in mmol/L
Sodium (Na⁺) 1 10 mmol/L
Potassium (K⁺) 1 10 mmol/L
Chloride (Cl⁻) 1 10 mmol/L
Bicarbonate (HCO₃⁻) 1 10 mmol/L
Calcium (Ca²⁺) 2 5 mmol/L
Magnesium (Mg²⁺) 2 5 mmol/L
Phosphate (PO₄³⁻) 3 3.33 mmol/L

In practice, the lab often reports either mmol/L or mEq/L depending on the analyte and local conventions. Understanding the role of the ion’s charge makes it easy to move between the two and compare results across different references or calculators.

Related conversions:

Related Calculators

meq/l to mmol/l Converter