Body Health CalculatorBlood Sugar Conversion Chart: mmol/L to mg/dL
Standard conversion: mg/dL = mmol/L × 18.0182. Fasting 5.6 mmol/L equals about 101 mg/dL. Keep a small chart for travel, research papers, and CGM exports that mix units.
Last updated: September 2026
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Why mmol/L and mg/dL both appear in care plans
Most US laboratory reports list plasma glucose in mg/dL. Canada, the UK, Australia, and many European countries use mmol/L on lab slips, research papers, and clinic handouts. If you read international guidelines, follow a study from abroad, or compare your home meter to a hospital discharge summary, you need the same number in both unit systems before you can judge whether it matches ADA diagnostic cutoffs or your personal targets.
Conversion does not change the underlying biology. It only rescales the number so you can line it up with the reference table your clinician uses. That step is routine for people who travel, students in health professions, and anyone whose continuous glucose monitor or app lets them switch display units.
Treat unit conversion as a bookkeeping step, not a diagnosis. A converted value still needs context: was the sample fasting for at least eight hours, taken two hours after an oral glucose tolerance drink, or drawn at random when you had symptoms? ADA criteria apply differently to each situation.
Standard conversion formula and rounding
Clinical software converts mmol/L to mg/dL by multiplying by 18.0182, the factor tied to the molar mass of glucose and IFCC reference procedures. Mental math often uses 18, which is fine for a single estimate but can drift if you convert hundreds of research values or build a spreadsheet for a quality-improvement project.
Worked example: 6.1 mmol/L × 18.0182 ≈ 109.9 mg/dL. That sits in the impaired fasting glucose band when the test was truly fasting. 7.0 mmol/L × 18.0182 ≈ 126 mg/dL, the fasting level at or above which diabetes is diagnosed when confirmed on repeat testing.
When you document conversions for your own records, note the raw mmol/L value, the factor you used, and the rounded mg/dL result. If a lab portal prints both units, prefer the portal pair over re-converting a rounded mmol/L value from a chart.
ADA thresholds in mmol/L and mg/dL
For fasting plasma glucose, ADA lists normal below 100 mg/dL (5.6 mmol/L), prediabetes from 100 to 125 mg/dL (5.6 to 6.9 mmol/L), and diabetes at 126 mg/dL (7.0 mmol/L) or higher when the test is repeated and meets diagnostic rules. Prediabetes can also be defined by A1c from 5.7% to 6.4% or by two-hour oral glucose tolerance results, so a single converted fasting number never tells the whole story.
Random plasma glucose at or above 200 mg/dL (11.1 mmol/L) can support a diabetes diagnosis when classic hyperglycemia symptoms are present. Two-hour values during a 75 g oral glucose tolerance test at or above 200 mg/dL (11.1 mmol/L) also meet diabetes criteria. Many adults with diagnosed type 2 diabetes aim to keep post-meal readings below 180 mg/dL (10.0 mmol/L) one to two hours after eating, though individualized targets from your care team override generic tables.
Screening guidelines recommend testing adults from age 35 at least every three years when results are normal, with more frequent checks for prediabetes or higher risk. Converted numbers help you compare a mmol/L result from travel clinics to the mg/dL targets you use at home, but screening frequency and treatment decisions stay with your clinician.
ADA reference points (plasma glucose, both units)
| Context | mg/dL | mmol/L |
|---|---|---|
| Normal fasting (upper limit) | <100 | <5.6 |
| Prediabetes fasting range | 100 to 125 | 5.6 to 6.9 |
| Diabetes fasting (confirmed) | ≥126 | ≥7.0 |
| Random with symptoms | ≥200 | ≥11.1 |
| Common post-meal goal (many T2D) | <180 | <10.0 |
Clinical use: fasting, post-meal, and lab versus meter
Fasting tests require no caloric intake for at least eight hours, usually drawn in the morning. Post-meal checks reflect how your body handled carbohydrate from a specific meal or glucose drink. Comparing a casual afternoon mmol/L reading to a fasting threshold table is a common mistake after conversion.
Laboratory plasma glucose and fingerstick capillary glucose are related but not identical. CDC materials note that meters must meet accuracy standards, yet they can still differ from the lab, especially when glucose is changing quickly. Convert first, then discuss discrepancies with your team rather than adjusting insulin from a single converted point.
If you are in prediabetes, converted values help you track progress alongside A1c. If you already take glucose-lowering medication, use conversion to understand foreign-language lab reports while keeping dose changes tied to verified patterns and clinician advice.
Travel, CGM exports, and dual-unit devices
Before international travel, set your meter or CGM app to the unit system you will see at your destination, or keep a one-page chart like the one below on your phone. Airport security generally allows medically necessary devices; carry prescriptions and pharmacy labels that describe your supplies in plain language.
When you download CGM data, some platforms default to mmol/L if the account region is outside the US. Export both units if available, or convert trend lines with the same factor every time so week-over-week comparisons stay honest. Sudden unit switches without conversion have caused people to misread highs as normal.
If you attend a clinic abroad, ask whether reported glucose is plasma-equivalent or whole-blood, and whether the draw was fasting. Write those notes next to the converted mg/dL value in your log so your home clinician can interpret the visit later.
mmol/L to mg/dL chart
Multiply each mmol/L value by 18.0182. The table rounds for readability at the bedside; use the full factor when you match a research paper or legal medical record.
Values near 3.9 mmol/L (about 70 mg/dL) often appear in hypoglycemia education materials, though individual alert thresholds depend on medications and history. Values near 11.1 mmol/L (200 mg/dL) align with random diagnostic cutoffs when symptoms are present.
FAQs
Should I use 18 or 18.0182 for daily logs?
Use 18.0182 when you compare against lab or ADA tables. Rounding to 18 is acceptable for a quick estimate but can accumulate error across many readings.
Does converting mmol/L to mg/dL diagnose diabetes?
No. Diagnosis requires the right test type, repeat confirmation when required, and sometimes A1c or oral glucose tolerance. Conversion only changes units.
My CGM shows mmol/L while my US lab uses mg/dL. What should I match?
Match the unit system your clinician uses for targets and medication changes. Convert consistently and bring both the raw export and your converted summary to visits.