Sodium mmol/L to mEq/L Converter
Convert serum sodium between mmol/L and mEq/L instantly, with mg/dL and mg/L results included. For sodium, the conversion is a simple 1:1.
Convert Sodium Units
Enter a sodium value, choose the unit you have, and the converter shows the equivalent in every common unit. Sodium (Na⁺) has a valence of 1, so mmol/L and mEq/L are numerically identical.
Sodium mmol/L to mEq/L Calculator
Convert in either direction with one click.
How the Conversion Works
Key concepts for converting sodium units correctly
Know the Valence
A milliequivalent equals millimoles multiplied by ionic charge. Sodium carries a charge of +1, so the multiplier is 1.
mmol/L Equals mEq/L
Because the multiplier is 1, a result of 140 mmol/L is exactly 140 mEq/L. The numbers never change, only the label does.
Converting to Mass Units
Multiply mmol/L by sodium’s molar mass of 22.99 to get mg/L, then divide by 10 for mg/dL. That is 2.299 mg/dL per mmol/L.
Check the Lab Range
Reference ranges differ slightly between laboratories and regions. Compare your value with the range printed on your own report.
Sodium Conversion Chart
Common serum sodium values converted between mmol/L, mEq/L and mg/dL, with a general indication of where each value sits against a typical adult range.
| Level | mmol/L | mEq/L | mg/dL | General Range |
|---|---|---|---|---|
| 120 | 120 | 275.9 | Below normal (low sodium) | |
| 130 | 130 | 298.9 | Below normal (low sodium) | |
| 135 | 135 | 310.4 | Lower limit of normal | |
| 140 | 140 | 321.9 | Normal | |
| 145 | 145 | 333.4 | Upper limit of normal | |
| 150 | 150 | 344.9 | Above normal (high sodium) | |
| 160 | 160 | 367.8 | Above normal (high sodium) |
Sodium Converter FAQ
Answers to the most frequently asked questions about converting sodium from mmol/L to mEq/L.
For sodium, the conversion is 1:1. Sodium has a valence of +1, so mEq/L = mmol/L × 1. A serum sodium of 140 mmol/L is therefore 140 mEq/L.
A milliequivalent is the number of millimoles multiplied by the ion’s charge (valence). Sodium (Na⁺) carries a single positive charge, so one millimole equals one milliequivalent.
A typical adult reference range for serum sodium is about 135 to 145 mmol/L (135 to 145 mEq/L). Ranges vary slightly between laboratories, so always compare your result with the range printed on your lab report.
Multiply mmol/L by 2.299 to get mg/dL. This uses sodium’s atomic weight of 22.99 g/mol divided by 10 to convert from mg/L to mg/dL. For example, 140 mmol/L is about 321.9 mg/dL.
The 1:1 rule applies to monovalent ions such as sodium, potassium and chloride. Divalent ions such as calcium and magnesium have a valence of 2, so their mEq/L value is twice their mmol/L value.