Instantly convert electrolyte lab values between conventional (US) and SI (international) units. Essential for interpreting lab results across different reporting systems. Select an electrolyte below to start converting.
Select an electrolyte, enter a value in any unit, and see instant conversions to all other units.
Choose from common clinical electrolytes
Select an electrolyte and enter a value to see conversions
Standard conversion factors for common clinical electrolytes.
| Electrolyte | Conventional Unit | SI Unit | Conversion Factor | Normal Range (Conventional) |
|---|---|---|---|---|
| Sodium (Na⁺) | mEq/L | mmol/L | ×1 (same) | 136 – 145 mEq/L |
| Potassium (K⁺) | mEq/L | mmol/L | ×1 (same) | 3.5 – 5.0 mEq/L |
| Chloride (Cl⁻) | mEq/L | mmol/L | ×1 (same) | 98 – 106 mEq/L |
| Bicarbonate (HCO₃⁻) | mEq/L | mmol/L | ×1 (same) | 22 – 28 mEq/L |
| Calcium (Ca²⁺) | mg/dL | mmol/L | ÷ 4.008 | 8.5 – 10.5 mg/dL |
| Magnesium (Mg²⁺) | mg/dL | mmol/L | ÷ 2.431 | 1.7 – 2.2 mg/dL |
| Phosphorus (PO₄) | mg/dL | mmol/L | ÷ 3.097 | 2.5 – 4.5 mg/dL |
| Glucose | mg/dL | mmol/L | ÷ 18.02 | 70 – 100 mg/dL |
| BUN (Urea Nitrogen) | mg/dL | mmol/L | ÷ 2.801 | 7 – 20 mg/dL |
| Creatinine | mg/dL | µmol/L | × 88.4 | 0.7 – 1.3 mg/dL |
Different countries and labs report values in different units — understanding conversions is essential for safe clinical practice.
The United States primarily uses conventional units (mg/dL, mEq/L) while most of the world uses SI (Système International) units (mmol/L, µmol/L). This creates challenges when interpreting lab results from different systems, reading international medical literature, or treating patients who bring results from abroad.
mEq/L (milliequivalents) measures the amount of a substance based on its chemical combining power — accounting for ionic charge. mmol/L (millimoles) measures the amount of substance regardless of charge. For monovalent ions (Na⁺, K⁺, Cl⁻), these are identical. For divalent ions (Ca²⁺, Mg²⁺), 1 mmol = 2 mEq because each ion carries two charges.
Quick rules of thumb for the most frequent conversions in clinical practice.
For sodium, potassium, chloride, and bicarbonate, the conventional and SI units are numerically identical. A sodium of 140 mEq/L is also 140 mmol/L. No conversion needed — just different labels for the same number.
For calcium and magnesium, each ion carries two charges. So 1 mmol/L equals 2 mEq/L. To convert mg/dL to mmol/L, divide by the molecular weight factor (4.008 for calcium, 2.431 for magnesium).
A fasting glucose of 100 mg/dL equals approximately 5.6 mmol/L. International diabetes guidelines use mmol/L: normal fasting glucose is < 5.6 mmol/L, diabetes is diagnosed at ≥ 7.0 mmol/L (equivalent to 126 mg/dL).
Creatinine uses µmol/L in SI units (not mmol/L). A creatinine of 1.0 mg/dL equals 88.4 µmol/L. Acute kidney injury is often defined as a rise ≥ 26.5 µmol/L (≈ 0.3 mg/dL) within 48 hours.
Answers to common questions about electrolyte unit conversions.