LDL Cholesterol Calculator
LDL from total, HDL, and triglycerides with bands and ratio.
What it does
Standard lipid panels measure total cholesterol, HDL, and triglycerides directly, then estimate LDL with the Friedewald equation from 1972: total minus HDL minus a fifth of triglycerides. Labs print that estimate on nearly every report.
The tool above runs the same equation from your three numbers. It returns LDL, the total to HDL ratio, and the LDL band.
LDL bands guide treatment thresholds: under 100 optimal, 130 to 159 borderline high, 160 plus high. Risk calculators blend LDL with age, pressure, smoking, and diabetes rather than treating one line.
High triglycerides break the estimate because the divide by five assumes typical VLDL composition. Past 400 mg/dL, direct LDL measurement replaces Friedewald math.
How to use
- Enter total cholesterol from the lab report.
- Enter HDL, the protective fraction.
- Enter fasting triglycerides.
- Read LDL with its band, then discuss targets with the clinician.
Formula
- total - HDL
- Non HDL cholesterol holding LDL plus remnants.
- trig / 5
- VLDL estimate from triglycerides.
- total / HDL
- Balance ratio between load and protection.
Millimole users divide each input by 38.67 for cholesterol or 88.57 for triglycerides first. The divide by five becomes divide by 2.2 in mmol/L.
Worked example
Example: total 200, HDL 50, triglycerides 100
Standard panel numbers in mg/dL.
- VLDL slice: 100 / 5 = 20.
- LDL: 200 - 50 - 20 = 130 mg/dL.
- Ratio: 200 / 50 = 4.0.
- Band: 130 to 159 reads borderline high.
Reference table
| LDL | Band | Direction |
|---|---|---|
| Under 100 | Optimal | Maintain |
| 100-129 | Near optimal | Watch lifestyle |
| 130-159 | Borderline high | Act on lifestyle |
| 160-189 | High | Clinician plan |
| 190+ | Very high | Treat promptly |
Limits
- Estimate, not measured LDL. High triglycerides break it.
- Single snapshot. Diet, illness, and labs vary.
- Bands guide, risk calculators decide treatment.
- Genetic conditions need specialist interpretation.
Common mistakes
- Fearing total while ignoring the HDL split.
- Testing non fasting and reading triglycerides high.
- Treating one panel as a verdict.
- Chasing LDL alone without pressure and smoking context.
- Stopping statins over muscle aches without calling.
Try it yourself
Quick checks. Answers sit tucked under each question.
Total 240, HDL 60, triglycerides 150?
LDL = 240 - 60 - 30 = 150 mg/dL, borderline high.
Ratio for those numbers?
240 / 60 = 4.0.
Questions
What is good LDL?
Under 100 mg/dL optimal for most. Higher risk patients target lower.
What raises HDL?
Exercise, healthy weight, and not smoking. Very high HDL needs context too.
Must I fast before the test?
Often yes for triglycerides. Follow the lab instructions on the order.
What is non HDL cholesterol?
Total minus HDL. It captures all atherogenic particles in one number.
When is LDL directly measured?
Past 400 triglycerides, and when precision guides treatment.
Do eggs drive cholesterol?
Less than once feared. Saturated fat moves LDL more than dietary cholesterol.