Cholesterol calculator
LDL cholesterol calculator
Most lab reports do not measure LDL directly. They calculate it from three other numbers on your lipid panel. Enter those numbers to see your LDL by two published equations.
Your lipid panel
Use numbers from the same blood test. Nothing you enter leaves this page.
What you will see
Your LDL by the Sampson and Friedewald equations, your non-HDL cholesterol and cholesterol ratio, and the healthy ranges for adults.
Educational only, not medical advice. Talk to your clinician about what your numbers mean for you.
Source
Sampson M et al., JAMA Cardiology 2020 (NIH equation). Friedewald WT et al., Clinical Chemistry 1972.
Validated in
Sampson: 18,715 test results from 8,656 patients, checked against the reference method (beta-quantification) and in more than 250,000 lab samples.
Limits
Friedewald is not used at triglycerides of 400 mg/dL or more; Sampson was built for levels up to 800. Above that, a lab can measure LDL directly. Not a substitute for your lab's own result.
Healthy cholesterol levels
MedlinePlus, from the US National Library of Medicine, lists these healthy ranges (MedlinePlus) (MedlinePlus):
| Test | Adults (20 and older) | Age 19 and younger |
|---|---|---|
| Total cholesterol | Under 200 mg/dL | Under 170 mg/dL |
| LDL ("bad") cholesterol | Under 100 mg/dL | Under 110 mg/dL |
| HDL ("good") cholesterol | 60 mg/dL or higher is best; low is under 40 (men) or under 50 (women) | Over 45 mg/dL |
| Non-HDL cholesterol | Under 130 mg/dL | Under 120 mg/dL |
| Triglycerides | Under 150 mg/dL | Different ranges; ask your child's clinician |
For triglycerides in adults, 150 to 199 mg/dL is borderline high, 200 to 499 is high, and 500 or more is very high (MedlinePlus). More in our triglycerides explainer.
These are general healthy ranges. Your own LDL goal can be lower, depending on your overall heart risk. Our heart risk calculator estimates that risk from your cholesterol, blood pressure and other numbers, and the statin eligibility check shows when the USPSTF recommends a statin.
Non-HDL cholesterol and the cholesterol ratio
Non-HDL cholesterol is total cholesterol minus HDL. It counts the cholesterol in LDL plus the particles that carry triglycerides. MedlinePlus lists under 130 mg/dL as healthy for adults and under 120 for children and teens (MedlinePlus).
The 2001 National Cholesterol Education Program report (ATP III) used non-HDL as a second target when triglycerides stay at 200 mg/dL or more, with a goal 30 mg/dL above the LDL goal for each risk group (NCEP ATP III):
| Risk group (ATP III) | LDL goal | Non-HDL goal |
|---|---|---|
| Heart disease, or a 10-year heart risk over 20% | Under 100 mg/dL | Under 130 mg/dL |
| 2 or more risk factors and a 10-year risk of 20% or less | Under 130 mg/dL | Under 160 mg/dL |
| 0 or 1 risk factor | Under 160 mg/dL | Under 190 mg/dL |
The same report classed LDL of 160 to 189 mg/dL as high and 190 or more as very high, total cholesterol of 240 or more as high, and HDL under 40 as low (NCEP ATP III). These goals date from 2001; your clinician may set yours from newer guidelines and your overall risk.
The total cholesterol to HDL ratio divides total cholesterol by HDL. For example, 200 mg/dL total and 50 mg/dL HDL gives a ratio of 4.0. The calculator shows it because many lab reports print it, but none of the sources used on this page sets a target for it, so we do not label any ratio as good or bad. LDL, HDL and non-HDL each have their own published ranges above.
How often to check, by age
MedlinePlus suggests a cholesterol test every 5 years for younger adults, every 1 to 2 years for men aged 45 to 65 and women aged 55 to 65, and every year after 65 (MedlinePlus). You may be asked to fast for 9 to 12 hours first (MedlinePlus). See cholesterol levels by age for the ranges and testing schedule at each age.
Why LDL is calculated
Measuring LDL directly takes a specialized method, so most labs calculate it and label it "calculated" on the report (MedlinePlus).
Friedewald (1972) was the standard for decades: LDL = total cholesterol − HDL − triglycerides ÷ 5, in mg/dL (Friedewald 1972). The triglycerides ÷ 5 part estimates the cholesterol carried in VLDL particles. The authors said not to use it when triglycerides are 400 mg/dL or more (Friedewald 1972).
Sampson (2020), from researchers at the NIH, keeps the same idea but fits the terms to data, so it holds up better at high triglycerides and low LDL. Compared against the reference method, it had a smaller average error (15.2 mg/dL) than Friedewald (32 mg/dL) or the Martin-Hopkins method (25.7 mg/dL), and 35% fewer misclassifications than Friedewald in people with high triglycerides (Sampson 2020). It can be used with triglycerides up to 800 mg/dL (Sampson 2020).
Common questions
Which LDL number should I trust?
The one on your lab report is the official result. If your lab uses Friedewald and your triglycerides are high or your LDL is low, the Sampson figure here may differ; that is a good question to bring to your clinician.
Do I need to fast?
Sometimes. MedlinePlus says you may need to fast for 9 to 12 hours, and your provider will tell you (MedlinePlus) (MedlinePlus).
What is non-HDL cholesterol?
It is total cholesterol minus HDL, so it counts all the cholesterol in particles other than HDL. MedlinePlus lists under 130 mg/dL as healthy for adults (MedlinePlus). See the non-HDL section above for the ATP III goals by risk group.
What is a good cholesterol ratio?
The total cholesterol to HDL ratio is easy to work out, but none of the sources we use sets a target for it. Look at your LDL, HDL and non-HDL against their ranges, and ask your clinician how they fit your overall heart risk.
How do I convert mmol/L to mg/dL?
For cholesterol, multiply mmol/L by 38.67. For triglycerides, multiply by 88.57. The calculator does this for you if you choose mmol/L.
See also which numbers to bring to a checkup and the child cholesterol screening check.
Sources
- Sampson M, Ling C, Sun Q, et al. A New Equation for Calculation of Low-Density Lipoprotein Cholesterol in Patients With Normolipidemia and/or Hypertriglyceridemia. JAMA Cardiol. 2020;5(5):540-548. doi.org/10.1001/jamacardio.2020.0013
- Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18(6):499-502. pubmed.ncbi.nlm.nih.gov/4337382/
- MedlinePlus (National Library of Medicine). Cholesterol Levels. medlineplus.gov/lab-tests/cholesterol-levels/
- MedlinePlus (National Library of Medicine). Triglycerides Test. medlineplus.gov/lab-tests/triglycerides-test/
- National Cholesterol Education Program. ATP III Guidelines At-A-Glance Quick Desk Reference. National Heart, Lung, and Blood Institute; NIH Publication No. 01-3305, 2001. www.nhlbi.nih.gov/files/docs/guidelines/atglance.pdf
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-30. Spotted an error? See About.