Cholesterol Ratio Calculator
Enter your lipid panel to find the three cholesterol ratios doctors watch most, total-to-HDL, LDL-to-HDL and triglyceride-to-HDL, plus your non-HDL cholesterol. Leave LDL blank and we will estimate it for you with the Friedewald equation. Each result is matched to its heart-risk band.
Formula
Worked example
With total 200, HDL 50, triglycerides 150 mg/dL: total/HDL = 200 / 50 = 4.0:1 (acceptable). Friedewald LDL = 200 - 50 - 150/5 = 120 mg/dL, so LDL/HDL = 120 / 50 = 2.4:1. TG/HDL = 150 / 50 = 3.0:1. Non-HDL = 200 - 50 = 150 mg/dL.
What the cholesterol ratios tell you
The total cholesterol to HDL ratio divides your total cholesterol by your HDL ("good") cholesterol. Because HDL helps clear cholesterol from your arteries, a higher HDL relative to total cholesterol produces a lower, more favourable ratio. The American Heart Association suggests aiming for a ratio below 5, with around 3.5 considered optimal. This calculator also reports two other ratios clinicians watch. The LDL/HDL ratio weighs "bad" against "good" cholesterol directly, with below 2.0 considered ideal. The triglyceride/HDL ratio is a simple stand-in for insulin resistance and small, dense LDL particles, and you read it against a different band depending on whether your lab uses mg/dL or mmol/L.
How LDL is estimated when you leave it blank
If your panel does not report LDL directly, leave the LDL field at zero and the calculator estimates it with the Friedewald equation: LDL equals total cholesterol minus HDL minus triglycerides divided by five (in mg/dL), or divided by 2.2 in mmol/L. That divisor approximates the cholesterol carried in VLDL particles. The Friedewald estimate is reliable when triglycerides are below about 400 mg/dL (4.5 mmol/L) and the sample is fasting; above that level the estimate drifts low, so enter a directly measured LDL instead. Whenever you type an LDL value, the calculator uses your number and skips the estimate.
Why non-HDL cholesterol matters too
Non-HDL cholesterol is simply your total cholesterol minus your HDL. It bundles together LDL ("bad") cholesterol and other atherogenic particles such as VLDL remnants, all of which can deposit cholesterol in artery walls. Many guidelines now treat non-HDL as a better predictor of cardiovascular events than LDL alone, partly because it needs no fasting and no special calculation. A lower non-HDL figure means fewer harmful particles in circulation, so it complements the three ratios when you assess heart risk.
How to improve all of these numbers
The ratios improve when total and LDL cholesterol or triglycerides fall, or when HDL rises, and lifestyle moves all of them at once. Regular aerobic exercise, replacing saturated and trans fats with unsaturated fats, cutting refined carbohydrates and alcohol to lower triglycerides, eating more soluble fibre, losing excess weight and not smoking all tend to help. When lifestyle changes are not enough, doctors may prescribe statins or other medicines. Track your numbers over time rather than reacting to a single reading, and interpret them alongside blood pressure and your overall risk profile.
Cholesterol ratio target bands
| Ratio | Ideal | Borderline | High risk |
|---|---|---|---|
| Total / HDL | Below 3.5 | 3.5 to 5.0 | Above 5.0 |
| LDL / HDL | Below 2.0 | 2.0 to 5.0 | Above 5.0 |
| TG / HDL (mg/dL) | Below 2.0 | 2.0 to 6.0 | Above 6.0 |
| TG / HDL (mmol/L) | Below 0.87 | 0.87 to 2.62 | Above 2.62 |
Lower is better for all three ratios. Total/HDL and LDL/HDL are unitless, so they read the same in mg/dL or mmol/L. The triglyceride/HDL band differs by unit because both values change. Targets follow the American Heart Association and the National Heart, Lung, and Blood Institute.
Frequently asked questions
What is a good cholesterol ratio?
The American Heart Association recommends keeping your total-to-HDL ratio below 5, and around 3.5 is often described as ideal. For the LDL/HDL ratio, below 2.0 is ideal and above 5.0 is high. For the triglyceride/HDL ratio, aim below 2.0 in mg/dL (or below 0.87 in mmol/L). Lower is better for all three.
How do you estimate LDL if it is not on my panel?
This calculator uses the Friedewald equation: LDL equals total cholesterol minus HDL minus triglycerides divided by five (mg/dL) or 2.2 (mmol/L). Leave the LDL field blank (zero) and enter your triglycerides to use it. The estimate is accurate for fasting samples with triglycerides below about 400 mg/dL; above that, ask for a directly measured LDL.
Are the ratios the same in mg/dL and mmol/L?
The total/HDL and LDL/HDL ratios are unitless, so they are identical whether your lab reports in mg/dL or mmol/L. The triglyceride/HDL ratio is different because triglycerides and HDL convert by different factors, so it is read against a separate band for each unit. Non-HDL cholesterol is a concentration and is reported in whichever unit you entered.
Does this replace a doctor’s assessment?
No. These figures are general guidance, not a diagnosis. True cardiovascular risk also depends on LDL particle number, blood pressure, age, smoking, diabetes and family history. Discuss your full lipid panel with a healthcare professional.