CalculatorsHeartLDL calculator
LDL calculator
Calculate your LDL with the newer NIH equation and the old one side by side, and see when they disagree.
123mg/dL
Near optimal
100 to 129 mg/dL is near optimal.
- Sampson (NIH) equation
- 123 mg/dL3.19 mmol/L
- Friedewald, the older one
- 120 mg/dLReads low when triglycerides are high
- Non-HDL cholesterol
- 150 mg/dLDoesn't need fasting
See the working
LDL = TC/0.948 − HDL/0.971 − (TG/8.56 + TG × nonHDL/2140 − TG²/16100) − 9.44TC 200, HDL 50, TG 150 mg/dL → 123.4 mg/dLMost LDL results are calculated
Labs usually don't measure LDL directly. They work it out from total cholesterol, HDL and triglycerides. Since 1972 most used the Friedewald equation, which gets less accurate as triglycerides rise and as LDL falls.
The NIH's Sampson equation, from 2020, holds up better in those cases, and works up to 800 mg/dL of triglycerides. That's why we lead with it and show Friedewald beside it.
LDL isn't the whole story
Non-HDL cholesterol counts all the cholesterol carried by particles that can get into artery walls, and it doesn't need fasting. ApoB counts those particles directly, and many cardiologists prefer it, especially when triglycerides are high.
Your target also depends on your whole risk, so it's a conversation with your doctor, not a number from a page.
Questions
Why doesn't this match my lab report?
Your lab may use Friedewald or another equation. Both are shown here so you can see the difference.
Do I need to fast?
Non-fasting panels are fine for most people. High triglycerides after a meal can pull a calculated LDL down, so a fasting repeat may be asked for.
What if my triglycerides are over 800 mg/dL?
No equation is reliable there. A direct LDL test or ApoB is the better read, and triglycerides that high are worth raising with your doctor soon.
What's a good LDL?
Under 100 mg/dL is what the guidelines call optimal for most people. If you've had a heart attack or stroke, or have diabetes, your doctor may aim lower.
Sources
- Sampson M et al. A new equation for calculation of low-density lipoprotein cholesterol in patients with normolipidemia and/or hypertriglyceridemia. JAMA Cardiology, 2020.
- Friedewald WT et al. Estimation of the concentration of LDL cholesterol in plasma. Clinical Chemistry, 1972.
Written by LifeFrom from the sources above, and not yet reviewed by a clinician. An estimate for your own understanding: it doesn't diagnose or treat anything, and it doesn't replace your doctor.
