LDL Cholesterol Calculator (Friedewald)
By Santaji GadepatilinUpdated October 27, 2026
LDL (“bad”) cholesterol can be estimated from total cholesterol, HDL and triglycerides with the Friedewald formula. This free LDL cholesterol calculator solves for whichever value you leave blank and shows the formula and steps.
How to use the LDL cholesterol calculator
Enter total cholesterol, HDL and triglycerides in mg/dL from your lipid profile. The calculator estimates LDL, non-HDL cholesterol and the total-to-HDL ratio.
This is for understanding results, not diagnosis. Discuss your numbers and overall cardiovascular risk with a doctor.
The Friedewald formula
LDL = Total cholesterol − HDL − Triglycerides ÷ 5
In mmol/L, use triglycerides ÷ 2.2 instead of ÷ 5.
Example
Total 200, HDL 50, triglycerides 150 mg/dL:
- LDL = 200 − 50 − 30 = 120 mg/dL
- Non-HDL = 150 mg/dL
- Total/HDL ratio = 4.0
General reference ranges (adults, mg/dL)
| Measure | Desirable | Borderline | High |
|---|---|---|---|
| Total cholesterol | under 200 | 200–239 | 240+ |
| LDL | under 100 | 130–159 | 160+ |
| HDL | 60+ (protective) | 40–59 | under 40 is low |
| Triglycerides | under 150 | 150–199 | 200+ |
| Non-HDL | under 130 | 130–159 | 160+ |
Ranges follow common US (NCEP ATP III) categories. Treatment targets depend on individual risk.
Unit conversion
| mg/dL | mmol/L (cholesterol) | mmol/L (triglycerides) |
|---|---|---|
| 50 | 1.29 | 0.56 |
| 100 | 2.59 | 1.13 |
| 130 | 3.36 | 1.47 |
| 150 | 3.88 | 1.69 |
| 200 | 5.17 | 2.26 |
| 240 | 6.21 | 2.71 |
| 300 | 7.76 | 3.39 |
Lowering LDL
Diet changes (less saturated and trans fat, more fibre), regular exercise, weight management and not smoking all help. Many people also need medication, depending on their risk. Follow your doctor’s advice.
Frequently asked questions
What is a healthy LDL level?
Under 100 mg/dL (2.6 mmol/L) is often described as optimal for most adults. Targets are lower for people at high cardiovascular risk — your doctor will set yours.
When is the Friedewald formula not accurate?
When triglycerides are 400 mg/dL or more, in non-fasting samples with high triglycerides, and at very low LDL levels. Labs may use the Martin–Hopkins or Sampson formulas or measure LDL directly.
How do I convert mmol/L to mg/dL?
Multiply cholesterol values by 38.67 and triglycerides by 88.57.
What is non-HDL cholesterol?
Total cholesterol minus HDL. It includes all the cholesterol carried by potentially harmful particles and does not need fasting.