Blood Sugar Unit Converter

Convert between mmol/L and mg/dL glucose units. Includes blood sugar level interpretation and clinical guidelines.

mmol/L to mg/dL

mmol/L
Enter glucose value in millimoles per liter
99.0 mg/dL
Converted to mg/dL

mg/dL to mmol/L

mg/dL
Enter glucose value in milligrams per deciliter
5.56 mmol/L
Converted to mmol/L
Fasting
Postprandial (2h after meal)
Random
Before Meal
After Meal
Bedtime
5.5 mmol/L
= 99 mg/dL (Normal fasting)
7.0 mmol/L
= 126 mg/dL (Diabetes threshold)
100 mg/dL
= 5.56 mmol/L (Normal fasting)
180 mg/dL
= 10.0 mmol/L (Postprandial target)
Calculating...
Blood Sugar Level Interpretation
5.5 mmol/L
= 99 mg/dL
Normal (Fasting)

This fasting glucose level is within the normal range.

Blood Sugar Classification

Glucose Level mmol/L mg/dL Interpretation

Estimated A1C (HbA1c) Calculator

Estimated hemoglobin A1c based on average blood glucose levels:

Enter your average blood glucose level
%
Estimated hemoglobin A1c percentage
Note: This is an estimation based on the formula: A1C = (Average Glucose + 46.7) / 28.7 (for mg/dL). Individual results may vary.

Understanding Blood Sugar Units

Blood glucose (blood sugar) is measured in two different units worldwide: millimoles per liter (mmol/L) and milligrams per deciliter (mg/dL). The conversion factor between these units is 1 mmol/L = 18.0182 mg/dL.

Regional Differences: mmol/L is used in most countries outside the United States (including Canada, Australia, the UK, and Europe). mg/dL is used primarily in the United States, Japan, and a few other countries.

Conversion Formulas

Blood Glucose Unit Conversion:
mg/dL to mmol/L: mmol/L = mg/dL ÷ 18.0182
mmol/L to mg/dL: mg/dL = mmol/L × 18.0182
Simplified Conversion (for clinical use):
mg/dL to mmol/L: mmol/L = mg/dL ÷ 18
mmol/L to mg/dL: mg/dL = mmol/L × 18
Clinical Context mmol/L mg/dL Interpretation
Normal Fasting 3.9 - 5.5 70 - 99 Normal glucose metabolism
Impaired Fasting (Prediabetes) 5.6 - 6.9 100 - 125 Increased risk of diabetes
Diabetes (Fasting) ≥ 7.0 ≥ 126 Diagnostic for diabetes
Normal Postprandial (2h) < 7.8 < 140 Normal after-meal response
Impaired Glucose Tolerance 7.8 - 11.0 140 - 199 Prediabetes range
Diabetes (Postprandial) ≥ 11.1 ≥ 200 Diagnostic for diabetes
Hypoglycemia < 3.9 < 70 Low blood sugar
Severe Hypoglycemia < 2.8 < 50 Requires immediate treatment
Hyperglycemia ≥ 11.1 ≥ 200 High blood sugar

Clinical Applications

Diabetes Diagnosis
Blood glucose levels are used to diagnose diabetes mellitus based on established thresholds for fasting and postprandial measurements.
Hypoglycemia Management
Identifying and treating low blood sugar is critical for diabetes management and prevention of complications.
Treatment Monitoring
Regular glucose monitoring helps assess the effectiveness of diabetes treatments including medications, diet, and exercise.
Gestational Diabetes
Pregnant women are screened for gestational diabetes using specific glucose thresholds during pregnancy.
Medication Adjustment
Insulin and oral diabetes medications are often adjusted based on blood glucose readings.
Complication Prevention
Maintaining glucose within target ranges helps prevent long-term complications like neuropathy, retinopathy, and nephropathy.

Target Ranges by Population

Population Fasting Target Postprandial Target A1C Target
Non-Diabetic Adults 70-99 mg/dL
(3.9-5.5 mmol/L) 		<140 mg/dL
(<7.8 mmol/L) 		<5.7%
Type 1 Diabetes 90-130 mg/dL
(5.0-7.2 mmol/L) 		<180 mg/dL
(<10.0 mmol/L) 		<7.0%
Type 2 Diabetes 80-130 mg/dL
(4.4-7.2 mmol/L) 		<180 mg/dL
(<10.0 mmol/L) 		<7.0%
Elderly with Diabetes 90-150 mg/dL
(5.0-8.3 mmol/L) 		<200 mg/dL
(<11.1 mmol/L) 		<8.0%
Gestational Diabetes <95 mg/dL
(<5.3 mmol/L) 		<120 mg/dL
(<6.7 mmol/L) 		<6.0%
Children with Diabetes 90-130 mg/dL
(5.0-7.2 mmol/L) 		<180 mg/dL
(<10.0 mmol/L) 		<7.5%

Understanding A1C (Hemoglobin A1c)

1

What is A1C? Hemoglobin A1c (glycated hemoglobin) reflects your average blood glucose levels over the past 2-3 months. It's expressed as a percentage and is a key marker for diabetes diagnosis and management.

2

Conversion to Glucose: A1C can be converted to an estimated average glucose (eAG) using the formula: eAG (mg/dL) = (28.7 × A1C) - 46.7. This helps patients understand what their A1C means in terms of daily glucose readings.

3

Diagnostic Values: An A1C of 5.7% to 6.4% indicates prediabetes, while an A1C of 6.5% or higher indicates diabetes. Below 5.7% is considered normal.

4

Limitations: A1C may be inaccurate in conditions that affect red blood cell turnover, such as anemia, kidney disease, or recent blood transfusions.

Clinical Note: Blood glucose targets should be individualized based on age, diabetes duration, comorbidities, and risk of hypoglycemia. Always consult with a healthcare provider to determine appropriate targets for your specific situation.

Frequently Asked Questions

The two units represent different measurement systems that evolved independently in different regions. mmol/L (millimoles per liter) is part of the International System of Units (SI) used in most countries. mg/dL (milligrams per deciliter) is a mass concentration unit used primarily in the United States and a few other countries. The conversion factor (1 mmol/L = 18.0182 mg/dL) comes from the molecular weight of glucose (180.182 g/mol).

Fasting glucose is measured after at least 8 hours of no caloric intake (usually in the morning before breakfast). Postprandial glucose is measured 1-2 hours after starting a meal. Both are important for diabetes diagnosis and management. Fasting glucose reflects baseline insulin production and sensitivity, while postprandial glucose reflects how well your body handles glucose from food.

The frequency depends on your diabetes type, treatment, and overall control. People with type 1 diabetes typically check 4-10 times daily. Those with type 2 diabetes on insulin may check 2-4 times daily, while those on oral medications might check 1-2 times daily or less frequently. Your healthcare provider will recommend a testing schedule based on your individual needs and treatment plan.

For hypoglycemia (low blood sugar): If below 70 mg/dL (3.9 mmol/L), consume 15-20 grams of fast-acting carbohydrates (glucose tablets, fruit juice, regular soda). Recheck in 15 minutes and repeat if still low. Follow with a snack or meal.

For hyperglycemia (high blood sugar): If consistently above target ranges, follow your healthcare provider's instructions, which may include adjusting medication, increasing physical activity, or modifying your meal plan. If blood sugar is extremely high (above 240 mg/dL or 13.3 mmol/L) and you have symptoms like excessive thirst, frequent urination, or confusion, contact your healthcare provider.

Yes, this converter works for any blood glucose measurement, including those from fingerstick meters, laboratory tests, and continuous glucose monitors (CGMs). The conversion factor is the same regardless of the measurement method. However, be aware that different devices may have slight variations in accuracy, and CGM readings may lag behind blood glucose by 5-15 minutes.