How to Convert HDL mmol/L to mg/dL
HDL cholesterol is reported in mmol/L in most countries and mg/dL in the US. Because it is cholesterol, it uses the same 38.67 factor as total and LDL cholesterol — only triglycerides are different.
HDL mg/dL = HDL mmol/L × 38.67 HDL mmol/L = HDL mg/dL ÷ 38.67 HDL mmol/L to mg/dL Chart
| mmol/L | mg/dL | Typical band |
|---|---|---|
| 0.8 mmol/L | 30.9 mg/dL | Low |
| 1.0 mmol/L | 38.7 mg/dL | Low / borderline (men) |
| 1.3 mmol/L | 50.3 mg/dL | Low / borderline (women) |
| 1.55 mmol/L | 59.9 mg/dL | Protective (~60) |
| 2.0 mmol/L | 77.3 mg/dL | High |
| 2.5 mmol/L | 96.7 mg/dL | Very high |
mg/dL to mmol/L Reverse Chart
| mg/dL | mmol/L |
|---|---|
| 40 mg/dL | 1.03 mmol/L |
| 50 mg/dL | 1.29 mmol/L |
| 60 mg/dL | 1.55 mmol/L |
| 80 mg/dL | 2.07 mmol/L |
HDL Reference Ranges
Unlike LDL, where lower is better, higher HDL is generally protective. Thresholds are sex-specific:
| Category | mg/dL | mmol/L |
|---|---|---|
| Low (higher risk) | Below 40 mg/dL (men) / below 50 mg/dL (women) | Below ~1.0 / 1.3 mmol/L |
| Acceptable | 40–59 mg/dL | ~1.0–1.5 mmol/L |
| Protective (optimal) | 60 mg/dL and above | 1.55 mmol/L and above |
Is More HDL Always Better?
HDL is the "good" cholesterol, and raising a low HDL is a common goal. But the benefit plateaus: very high HDL — above roughly 90–100 mg/dL (2.3–2.6 mmol/L) — has not been shown to add extra protection, and some studies link extreme levels to higher, not lower, risk. HDL is best read as part of the whole panel, not chased on its own.
HDL and the Cholesterol Ratio
HDL is used in the total cholesterol to HDL ratio (total ÷ HDL; below about 3.5 is favorable) and in the non-HDL cholesterol figure (total − HDL). Both are worked out on the cholesterol conversion calculator, which also converts LDL and total cholesterol.
Worked Example
Suppose your HDL is 1.3 mmol/L and you want mg/dL:
1.3 × 38.67 = 50.3 mg/dL 50 mg/dL is the low-HDL threshold for women. For the reverse direction, 40 mg/dL — the men's threshold — is about 1.03 mmol/L.
Frequently Asked Questions
How do you convert HDL mmol/L to mg/dL?
Multiply mmol/L by 38.67. For example, 1.55 mmol/L is about 60 mg/dL.
What is a good HDL level?
60 mg/dL (1.55 mmol/L) or above is protective; below 40 mg/dL (men) or 50 mg/dL (women) is low.
Why does HDL use 38.67 like LDL?
They are all cholesterol and share the same molecular weight; only triglycerides use 88.57.
Can HDL be too high?
Very high HDL does not add benefit and is sometimes linked to higher risk, so it is read with the whole panel.
References
- HDL conversion factor 38.67 (mmol/L ↔ mg/dL) and sex-specific HDL reference thresholds (NCEP/ATP and standard clinical laboratory references).
- Omni Calculator — Cholesterol units converter.
Conclusion
Converting HDL between mmol/L and mg/dL is a simple ×38.67, the same as total and LDL cholesterol. The key difference is direction: for HDL, higher is better — up to a point. Interpret it with your full lipid panel and healthcare provider.