Diabetes & Metabolic Health
HbA1c, blood glucose and how the body handles sugar.
Metabolic health is assessed mainly through blood glucose — measured directly at a moment in time, or indirectly over months through HbA1c. The two answer different questions. A fasting glucose says where you are right now; an HbA1c summarizes roughly the previous two to three months. Both come with units that differ by country, thresholds that are screening ranges rather than diagnoses, and a set of circumstances in which they mislead. This hub covers what each measurement reflects, how to convert between mg/dL and mmol/L, and why clinicians rarely act on a single result.
Diabetes & Metabolic Health tools
Calculators and converters for the measurements in this area.
HbA1c to eAG
Diabetes & Metabolic Health
Convert an HbA1c percentage into an estimated average blood glucose.
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Glucose Converter
Diabetes & Metabolic Health
Convert blood glucose between mg/dL and mmol/L in either direction.
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Waist-to-Height
General Wellness
Divide your waist by your height and read the result against the bands NICE publishes.
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Diabetes & Metabolic Health guides
Plain-English explanations of what these measurements mean.
Heart HealthCardiovascular-Kidney-Metabolic Syndrome: Why Doctors Now Link the Heart, Kidneys and Metabolism
The American Heart Association now describes weight, blood sugar, blood pressure, cholesterol, kidney function and heart disease as one connected syndrome with five stages. Here…
8 min read
NutritionCarbs, Protein and Fat: What the Official Macronutrient Ranges Mean
US reference ranges allow carbohydrate to supply 45 to 65 percent of calories, fat 20 to 35 percent and protein 10 to 35 percent. The ranges are deliberately wide, and a split i…
8 min read
Heart HealthHow Heart Disease Risk Is Estimated: The PREVENT Equations Explained
The American Heart Association’s PREVENT equations estimate a person’s 10- and 30-year risk of cardiovascular disease from blood pressure, cholesterol, diabetes, smoking, age an…
8 min read
General WellnessWaist Circumference, Waist-to-Height and Waist-to-Hip Ratio Explained
Where weight is carried says something that BMI cannot. Waist circumference, waist-to-height ratio and waist-to-hip ratio each measure central fat in a different way, with cut-p…
8 min read
Diabetes & Metabolic HealthBlood Glucose Units Explained: mg/dL, mmol/L and A1C in mmol/mol
The same glucose result can be written in mg/dL or mmol/L, and A1C in percent or mmol/mol. The conversions are exact arithmetic, but they change how a number is written, not wha…
7 min read
General WellnessBMI Categories Around the World: WHO, CDC and the Asian Action Points
The adult BMI categories used by the WHO and the CDC are the same, but the WHO has also suggested additional action points at 23.0 and 27.5 for some Asian populations. Here is h…
7 min read
Diabetes & Metabolic HealthWhat Does HbA1c Mean?
HbA1c measures the percentage of your hemoglobin that has glucose attached to it, which reflects your average blood glucose over roughly the previous two to three months. It is…
9 min read
Diabetes & Metabolic HealthA1C vs Fasting Blood Sugar: What’s the Difference?
A fasting blood sugar test measures glucose at one moment after not eating; A1C reflects average glucose over two to three months. They answer different questions, they can disa…
7 min read
Blood TestsHow to Read Common Blood Test Results
A reference range is built to include about 95% of a healthy population, which means roughly one result in twenty falls outside it by design. This guide explains what the most c…
9 min read
Learn this topic
Guided journeys and short quizzes. Progress is kept in your browser — no account needed.
Understand Your A1C
Work through what HbA1c measures, how it relates to day-to-day glucose, and where it can mislead.
5 steps
Understanding HbA1c
Four questions on what HbA1c measures, the period it covers, and when it can be misleading.
4 questions