LDL Cholesterol Calculator (Friedewald)
Estimate LDL cholesterol from total cholesterol, HDL and triglycerides using the Friedewald equation (mg/dL): LDL = TC − HDL − TG/5.
How to use this tool
- Enter total cholesterol in mg/dL.
- Enter HDL cholesterol in mg/dL.
- Enter triglycerides in mg/dL (must be under 400 for a valid result).
- Read your estimated LDL cholesterol and category.
The Friedewald LDL calculator estimates your LDL ('bad') cholesterol from total cholesterol, HDL and triglycerides — the same calculation most lab lipid panels use.
Formula
LDL = total cholesterol − HDL − (triglycerides ÷ 5)
All values are in mg/dL. The TG/5 term estimates VLDL cholesterol. The equation is not valid when triglycerides reach 400 mg/dL or more.
How it works
The Friedewald equation estimates LDL ('bad') cholesterol without measuring it directly, by subtracting HDL and an estimate of VLDL from total cholesterol. VLDL is approximated as triglycerides divided by 5, a ratio that holds reasonably well at typical triglyceride levels in mg/dL. Most lab lipid panels report a calculated LDL derived this way.
The estimate degrades as triglycerides rise and becomes invalid at 400 mg/dL or above, where the TG/5 assumption breaks down; in that case a direct LDL measurement or the Martin-Hopkins method is used. It also assumes a fasting sample. The interpretation bands shown are general LDL categories, not a treatment recommendation.
This calculator is provided for general information and education only and is not medical advice. Clinical formulas are screening and estimation tools, not diagnoses, and they assume valid, correctly-measured inputs. Always consult a qualified clinician before making any decision about your health.
Worked example
TC 200, HDL 50, TG 150 mg/dL
- Estimate VLDL: TG ÷ 5 = 150 ÷ 5 = 30 mg/dL
- Subtract HDL and VLDL from total: 200 − 50 − 30
- = 120 mg/dL
- Round to two decimals = 120.00 mg/dL
Estimated LDL cholesterol = 120.00 mg/dL (Near optimal)
LDL cholesterol categories (mg/dL)
| LDL range | Category |
|---|---|
| < 100 | Optimal |
| 100 – 129 | Near optimal |
| 130 – 159 | Borderline high |
| 160 – 189 | High |
| ≥ 190 | Very high |
Key terms
- LDL cholesterol
- Low-density lipoprotein cholesterol, the fraction most strongly linked to atherosclerotic cardiovascular risk.
- HDL cholesterol
- High-density lipoprotein cholesterol, which helps remove cholesterol from the bloodstream.
- Triglycerides
- The main storage form of fat in blood; used here to estimate VLDL cholesterol via the TG/5 term.
- Friedewald equation
- The 1972 formula LDL = TC − HDL − TG/5 used to calculate LDL from a standard lipid panel.
Frequently asked questions
- When is the Friedewald LDL not valid?
- It is unreliable and not used when triglycerides are 400 mg/dL or higher, because the triglycerides-divided-by-5 estimate of VLDL no longer holds. A direct LDL measurement is preferred then.
- Do I need to fast before the test?
- The Friedewald estimate assumes a fasting lipid panel, since recent meals raise triglycerides and distort the VLDL term and therefore the LDL estimate.
- What is a healthy LDL level?
- An LDL below 100 mg/dL is generally considered optimal for most adults, but individual targets depend on overall cardiovascular risk and should be set with a clinician.