Sodium mmol/L To mEq/L Converter
Convert sodium results between mmol/L and mEq/L. For sodium, the numeric value is the same because sodium has a charge of plus one.
Sodium Conversion Result
mmol/L to mEq/L140.0 mEq/L
140 mmol/L equals 140 mEq/L for sodium because sodium is monovalent. This is a unit conversion only.
140.0 mmol/L
140.0 mEq/L
322.0 mg/dL
x 1
+1
22.98976928
Unit conversion only
Quick Conversions
For sodium, mmol/L and mEq/L have the same numeric value. A sodium result of 140 mmol/L is 140 mEq/L. A sodium result of 138 mEq/L is 138 mmol/L. The equality happens because sodium has a single positive charge. That rule cannot be copied blindly to ions with a charge of two or three.
| Sodium mmol/L | Sodium mEq/L | Approx mg/dL | How To Read The Row |
|---|---|---|---|
| 120 mmol/L | 120 mEq/L | 276 mg/dL | Same mmol/L and mEq/L value; lab interpretation is not provided here. |
| 130 mmol/L | 130 mEq/L | 299 mg/dL | Conversion only; compare with the reporting lab’s range if needed. |
| 135 mmol/L | 135 mEq/L | 310 mg/dL | Common result format on many UK electrolyte panels. |
| 140 mmol/L | 140 mEq/L | 322 mg/dL | Default example for checking the equality. |
| 145 mmol/L | 145 mEq/L | 333 mg/dL | Same numeric value in mEq/L because sodium is monovalent. |
| 150 mmol/L | 150 mEq/L | 345 mg/dL | Do not use this table to decide urgency. |
Conversion Formula And Method
mEq/L = mmol/L x ionic valence.
For sodium, ionic valence = 1.
Sodium mEq/L = sodium mmol/L x 1.
Sodium mmol/L = sodium mEq/L / 1.
mg/dL = mmol/L x atomic weight / 10.
For sodium, mg/dL = mmol/L x 22.98976928 / 10.
The mEq/L unit expresses chemical equivalents, which include charge. Sodium ions carry one positive charge, so one millimole of sodium is one milliequivalent. Calcium, magnesium and other ions with a different charge do not follow the same numeric equality. Always use the analyte-specific conversion factor.
Step-By-Step Sodium Unit Check
Copy The Lab Unit
Read whether the report says mmol/L, mEq/L or mg/dL. Do not guess from the number alone because countries and systems can differ.
Apply The Sodium Factor
For mmol/L to mEq/L, multiply by 1. For mEq/L to mmol/L, divide by 1. The value is unchanged.
Keep The Clinical Context
Use the converted unit for comparison or documentation, then read the original lab report, reference interval and clinician advice.
mmol/L, mEq/L And mg/dL Compared
| Unit | Meaning | Best Use | Important Limit |
|---|---|---|---|
| mmol/L | Millimoles per litre, amount of substance per volume. | Common in UK and many international chemistry reports. | Does not include charge unless the analyte has a known valence. |
| mEq/L | Milliequivalents per litre, amount adjusted for ionic charge. | Older electrolyte references and some clinical materials. | Not always numerically equal to mmol/L for other ions. |
| mg/dL | Milligrams per decilitre, mass per volume. | Some international reports or old reference material. | Needs molecular or atomic weight to convert. |
| Reference interval | Lab-specific comparison range. | Interpreting a report with clinical context. | This converter does not judge whether a value is suitable. |
Clinical Boundary Notes
Do Not Diagnose From Conversion
The converter cannot decide hyponatraemia, hypernatraemia, dehydration, kidney disease, medication effect or treatment urgency. It only changes the unit label.
Use The Lab Report
Reference intervals, specimen type, timing, symptoms and repeat testing can all matter. Laboratories may flag results using their own reporting rules.
When To Seek Help
Contact a doctor or urgent service if the report or symptoms suggest a concern. Severe symptoms, confusion, seizures, collapse, marked dehydration or rapid changes need prompt professional assessment.
Copying Sodium Results Between Records
When moving a sodium result from one record to another, copy the value, the unit, the specimen type, the date and the laboratory comment. A bare number can be misleading because serum, plasma and urine sodium are used for different clinical questions. The unit conversion may be simple, but the record still needs enough context for a clinician to recognise where the number came from.
If a form asks for mEq/L and the UK report says mmol/L, sodium can usually be copied with the same numeric value after checking that the analyte is sodium. For example, 139 mmol/L can be entered as 139 mEq/L if the form requires mEq/L. Do not use that shortcut for calcium, magnesium or phosphate without the correct charge and formula. If the destination form asks whether the result is acceptable, out of range or urgent, leave that judgement to the lab report or medical professional.
For screenshots, patient notes or insurance forms, keep the original unit visible. If you also include the converted unit, label it clearly as a conversion. That reduces the risk of someone reading mg/dL, mmol/L and mEq/L as interchangeable labels. It also helps later review if a value is queried.
Sodium Unit Converter FAQ
Is sodium mmol/L the same as mEq/L?
Yes, for sodium the numeric value is the same because sodium has a valence of one. For example, 140 mmol/L equals 140 mEq/L.
Can I use this formula for potassium?
Potassium is also monovalent, so the same mmol/L and mEq/L equality applies to potassium. Do not assume this for ions with a different charge.
Why does the converter show mg/dL?
Some reference material uses mass concentration. The mg/dL estimate uses sodium’s atomic weight. It is included for unit comparison, not for clinical interpretation.
Does this tell me if my sodium is normal?
No. The page does not judge normality, severity or treatment. Use the reference interval on the laboratory report and advice from a clinician.
Should I round sodium results?
Use the same precision as the original report unless a clinician or lab gives another format. Whole numbers are common for sodium in mmol/L.
Can I convert urine sodium with this tool?
Yes, if the unit is mmol/L or mEq/L, the arithmetic is the same. The clinical meaning of urine sodium is different from blood sodium and needs professional context.
Sources
- Regenstrief Institute. (2024). Unified Code for Units of Measure. UCUM. https://ucum.org/
- Bureau International des Poids et Mesures. (2022). The International System of Units, 9th ed. BIPM. https://www.bipm.org/en/publications/si-brochure
- National Institute of Standards and Technology. (2008). Guide for the Use of the International System of Units (SI). NIST Special Publication 811. https://www.nist.gov/pml/special-publication-811
- Royal College of Pathologists. (n.d.). Patient Safety And Laboratory Medicine. RCPath. https://www.rcpath.org/