LDL cholesterol (low-density lipoprotein cholesterol, often called "bad" cholesterol) is the amount of cholesterol carried in LDL particles, the main particles that build up as plaque in artery walls.
Also called: LDL-C, low-density lipoprotein cholesterol, bad cholesterol.
General information, not medical advice
Ranges and goals vary with your overall heart risk and between labs. Go through your own results with your doctor or another qualified health professional.
What it measures
LDL cholesterol is the concentration of cholesterol inside LDL particles, reported in mg/dL in the US and mmol/L in the UK, Europe, Canada and Australia. It's the cholesterol content of the particles, not how many there are (that's ApoB).
Many labs calculate LDL from your total cholesterol, HDL and triglycerides instead of measuring it. The 2026 ACC/AHA guideline prefers the newer Martin/Hopkins or Sampson/NIH equations to the older Friedewald formula, which is less accurate when triglycerides are high or LDL is very low.
Normal and target ranges
| LDL | mg/dL | mmol/L |
|---|---|---|
| Optimal | Under 100 | Under 2.6 |
| Near optimal | 100–129 | 2.6–3.3 |
| Borderline high | 130–159 | 3.4–4.1 |
| High | 160–189 | 4.1–4.9 |
| Very high | 190 and above | 4.9 and above |
These are the general US categories (MedlinePlus). In the UK, HEART UK gives below 3.0 mmol/L (116 mg/dL) as a healthy level for adults.
People on treatment have lower goals. Under the 2026 ACC/AHA guideline the LDL goal is under 55 mg/dL (1.4 mmol/L) with heart disease at very high risk, under 70 mg/dL (1.8 mmol/L) with heart disease or a PREVENT risk of 10% or more, and under 100 mg/dL (2.6 mmol/L) at borderline or intermediate risk on a statin. NICE (UK) aims for 2.0 mmol/L or less in people who already have heart or artery disease.
What raises and lowers it
- Raises it: saturated and trans fat, and to a lesser degree dietary cholesterol; weight gain; inherited high cholesterol (familial hypercholesterolaemia), which an LDL of 190 mg/dL (4.9 mmol/L) or more can point to. In women, LDL often rises around menopause.
- Lowers it: swapping saturated fat for unsaturated fat, soluble fibre and other diet changes; statins (moderate intensity cuts LDL by 30–49%, high intensity by 50% or more); and other medicines such as ezetimibe and PCSK9 inhibitors.
Deeper reading
Related terms
- ApoB
- HDL cholesterol
- Lipoprotein(a)
- Non-HDL cholesterol
- PREVENT risk calculator
- Triglycerides
- VLDL cholesterol
- All glossary terms
Frequently asked questions
What is a normal LDL cholesterol level?
For most adults, under 100 mg/dL (2.6 mmol/L) is optimal by US categories, and HEART UK gives below 3.0 mmol/L as healthy. People with heart disease or a high 10-year risk have lower goals: under 70 mg/dL (1.8 mmol/L) or under 55 mg/dL (1.4 mmol/L) under the 2026 ACC/AHA guideline.
Why is LDL called bad cholesterol?
LDL particles carry cholesterol into artery walls, where it builds up as plaque that can narrow arteries and lead to heart attacks and strokes. That's why LDL is the main target of diet changes and cholesterol medicines.
Is LDL measured or calculated?
Usually calculated from total cholesterol, HDL and triglycerides. The 2026 ACC/AHA guideline prefers the Martin/Hopkins or Sampson/NIH equations over the older Friedewald formula. Some labs measure LDL directly, especially when triglycerides are high.
Sources
- Blumenthal RS, Morris PB, et al. 2026 ACC/AHA Guideline on the Management of Dyslipidemia. J Am Coll Cardiol. 2026;87(19). Also in Circulation, doi:10.1161/CIR.0000000000001423.
- MedlinePlus: LDL, the "bad" cholesterol
- HEART UK: Understanding your cholesterol test results
- NICE NG238: Cardiovascular disease risk assessment and reduction, including lipid modification
Track your numbers over time
Heart Tracker logs every cholesterol test in mg/dL or mmol/L and charts your total cholesterol, LDL, HDL and triglycerides over time, next to what you were eating. Free on iPhone, no account needed.
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