Lab Unit Converter (US ↔ SI) for Nurses
Convert common lab values between US conventional units (mg/dL, mEq/L) and SI units (mmol/L, µmol/L). Supports glucose, cholesterol, calcium, and more.
Fast US ↔ SI conversions with reference ranges. Common analytes covered.
How This Calculator Works
Formula
Common conversion factors; Na/K mmol/L ↔ mEq/L are 1:1.
References
- Kratz A, Ferraro M, Sluss PM, Lewandrowski KB. Laboratory Reference Values. N Engl J Med. 2004;351(15):1548-1563.
- National Institute of Standards and Technology (NIST). Guide for the Use of the International System of Units (SI). 2008.
- CLSI C28-A3c: Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory. 3rd ed. Clinical and Laboratory Standards Institute; 2010.
Educational tool only. Verify dosing and policies per your facility. Not a substitute for clinical judgment.
Common clinical questions about this calculator and its applications
Why do different countries use different lab units?
The US primarily uses conventional units (mg/dL, mEq/L) while most other countries use SI units (mmol/L). SI units are based on molecular concentration, making them more scientifically consistent. Understanding both is important for international literature review and when working with patients from different regions.
Which unit system should I use for calculations?
Use whichever unit system your facility uses for consistency and to prevent errors. However, many clinical guidelines and research studies use SI units, so being able to convert is essential. Drug dosing often uses conventional units in the US, while international protocols use SI.
Are conversion factors always constant?
Most are constant (glucose: ÷18 or ×18), but some vary by the specific substance being measured. For example, conversion of cholesterol, triglycerides, and different electrolytes each have unique factors based on their molecular weights. Always verify conversion factors for critical values.
Why is glucose conversion important in diabetes management?
Many continuous glucose monitors and international diabetes guidelines use mmol/L, while US hospitals typically use mg/dL. Being able to quickly convert (mg/dL ÷ 18 = mmol/L, or mmol/L × 18 = mg/dL) helps interpret results and communicate with patients who may use different monitoring systems or have received care abroad.
What about units for medications vs. labs?
Medication concentrations (like insulin units, or antibiotic mg/kg) are separate from lab value units. Don't confuse serum potassium (mEq/L or mmol/L) with potassium supplementation doses (mEq administered). The lab value measures concentration in blood; the medication dose is the amount given.
About Our Validation & Sources
All calculators on Nurside use evidence-based formulas from standard clinical practice guidelines. Our validation thresholds are derived from clinical experience, published literature, and expert consultation.
Safety Features: Built-in validation catches common entry errors (like unit confusion), flags unusually high or low values, and requires explicit confirmation for potentially dangerous calculations. This is designed to support, not replace, your clinical judgment.
Formula Transparency: Click "Methods Used" in any calculator to see the exact formula and safety thresholds being applied. We believe you should always understand how your clinical tools work.
Educational Purposes Only: These calculators are provided for educational and clinical support purposes. They do not constitute medical advice and should not replace independent clinical judgment. Always verify calculations against your facility's protocols and the patient's specific clinical context.