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Beta-hydroxybutyrate in two units: the short answer
To convert beta-hydroxybutyrate from mg/dL to mmol/L, multiply by 0.0961. To go back from mmol/L to mg/dL, multiply by 10.41 (or divide by 0.0961). For example, 15.6 mg/dL × 0.0961 = 1.5 mmol/L. The converter above works in both directions and shows where the result sits against typical reference ranges.
What the test measures
Beta-hydroxybutyrate (BHB) is the main ketone measured by blood ketone meters and labs. Meters show mmol/L; some US labs report mg/dL. BHB's molar mass is 104.1 g/mol, so 1 mg/dL = 0.0961 mmol/L and 1 mmol/L = 10.4 mg/dL.
Why the units differ
Diabetic ketoacidosis guidance and sick-day rules use mmol/L, so a lab result in mg/dL must be converted to judge it against those thresholds.
Where the factor comes from
The conversion factor comes from the molar mass (104.1 g/mol) and the volume units on each side. Laboratories may round the factor slightly differently, which can change the last digit but never the clinical meaning.
How to convert step by step
- Check the unit printed next to the result on your report – mg/dL or mmol/L.
- mg/dL → mmol/L: multiply by 0.0961.
- mmol/L → mg/dL: multiply by 10.41.
- Round to the same number of decimals your lab uses.
Worked example in reverse: 0.5 mmol/L × 10.41 = 5.2 mg/dL.
Beta-hydroxybutyrate conversion chart
| mg/dL | mmol/L |
|---|---|
| 2 | 0.2 |
| 4 | 0.4 |
| 5 | 0.5 |
| 6.2 | 0.6 |
| 10 | 1 |
| 15.6 | 1.5 |
| 20 | 1.9 |
| 31.2 | 3 |
| 40 | 3.8 |
| 50 | 4.8 |
| mmol/L | mg/dL |
|---|---|
| 0.2 | 2.1 |
| 0.4 | 4.2 |
| 0.5 | 5.2 |
| 0.6 | 6.2 |
| 1 | 10.4 |
| 1.5 | 15.6 |
| 1.9 | 19.8 |
| 3 | 31.2 |
| 3.8 | 39.5 |
| 4.8 | 49.9 |
Beta-hydroxybutyrate levels: what the numbers mean
| Category | mg/dL | mmol/L |
|---|---|---|
| Normal<0.6 mmol/L | < 6.2 | < 0.6 |
| Raised ketones0.6–3.0 mmol/L – follow sick-day advice if you have diabetes | 6.3 – 31.2 | 0.6 – 3 |
| High – DKA range if glucose high/acidosis≥3.0 mmol/L – seek urgent care if you have diabetes | ≥ 31.3 | ≥ 3 |
Thresholds as used in diabetes sick-day guidance and DKA definitions. Nutritional ketosis on a low-carb diet usually stays around 0.5–3 mmol/L with normal glucose.
Thresholds as used in diabetes sick-day guidance and DKA definitions. Nutritional ketosis on a low-carb diet usually stays around 0.5–3 mmol/L with normal glucose.
Interpreting beta-hydroxybutyrate results
Ketones are made from fat when the body lacks usable glucose – during fasting, very low-carbohydrate diets, prolonged exercise, or insulin deficiency. In diabetes, rising ketones plus high glucose signal possible ketoacidosis, a medical emergency. SGLT2-inhibitor medicines can cause 'euglycemic' DKA with near-normal glucose, so ketone checks matter when someone on these drugs feels unwell.
A single result outside the reference range is common and often not significant on its own. Reference ranges are set so that about 1 in 20 healthy people fall outside them, and every laboratory sets its own limits for its method. Use the range printed on your report and discuss results with the clinician who ordered the test.
When to see a doctor
Contact your clinician if a result is flagged as abnormal and you have symptoms, if a value is far outside the range, or if results are changing over time. This page explains units; it cannot diagnose or replace medical advice.
Frequently asked questions
What is 1.5 mmol/L ketones in mg/dL?
1.5 × 10.4 = 15.6 mg/dL.
Are blood ketones on keto dangerous?
In people without diabetes, nutritional ketosis rarely exceeds 3 mmol/L and is not ketoacidosis. In type 1 diabetes or with SGLT2 inhibitors, raised ketones need prompt attention even if glucose looks normal.
Can I use this converter for any lab?
Yes for the unit conversion, which is fixed by chemistry. Reference ranges differ between labs and methods, so compare your converted value with your own lab's range.