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Cholesterol Calculator

Use this free cholesterol calculator to make sense of your lipid panel. Enter your total cholesterol, HDL, LDL, and triglycerides — in mg/dL or mmol/L — and the calculator works out your TC/HDL ratio, your LDL/HDL ratio, and your non-HDL cholesterol, then labels each value using the ATP III and American Heart Association ranges: desirable, borderline, or high. One number never tells the whole story, so the calculator shows all of them together, the way a doctor reads a panel.

How the cholesterol calculation works

A lipid panel reports four numbers, and each one means something different. Total cholesterol is the sum of all the cholesterol in your blood. HDL, the "good" cholesterol, carries cholesterol away from the arteries and back to the liver, so higher is better. LDL, the "bad" cholesterol, deposits cholesterol in artery walls, so lower is better. Triglycerides are a different kind of blood fat that rises after meals and with excess sugar, alcohol, and weight, and high levels add to heart risk.

The calculator turns those four numbers into three derived figures. The TC/HDL ratio divides total cholesterol by HDL: a total of 200 and an HDL of 50 gives 4.0. Lower is better, because the ratio improves either when total cholesterol falls or when HDL rises. The LDL/HDL ratio does the same for the two main fractions: 130 divided by 50 is 2.6. Non-HDL cholesterol is total minus HDL, which counts every artery-clogging particle — LDL plus VLDL and the rest — in one number: 200 minus 50 is 150.

Categories follow the ATP III guidelines and the American Heart Association ranges. Total cholesterol under 200 mg/dL is desirable, 200 to 239 is borderline high, and 240 or above is high. LDL under 100 is optimal, 100 to 129 is near or above optimal, 130 to 159 is borderline high, 160 to 189 is high, and 190 or above is very high. HDL under 40 in men and under 50 in women is low; 60 or above is high and protective. Triglycerides under 150 are normal, 150 to 199 are borderline high, 200 to 499 are high, and 500 or above are very high.

Non-HDL cholesterol gets its own targets because it catches risk that LDL alone can miss. Under 130 mg/dL is optimal, 130 to 159 is near optimal, 160 to 189 is borderline high, 190 to 219 is high, and 220 or above is very high. Doctors often use non-HDL as the second target when triglycerides are high, since the Friedewald LDL estimate becomes unreliable above 400 mg/dL of triglycerides. If your lab did not measure LDL directly, leave that field blank and the calculator estimates it with the Friedewald formula — but only when triglycerides are under 400 mg/dL; above that, it will tell you the estimate is not valid.

Units matter because labs outside the US report in mmol/L. To convert cholesterol (total, HDL, LDL), divide mg/dL by 38.67; to convert triglycerides, divide by 88.57. A total of 200 mg/dL is 5.17 mmol/L, an HDL of 50 mg/dL is 1.29 mmol/L, and triglycerides of 150 mg/dL are 1.69 mmol/L. The unit switch on this calculator converts your entries and shows every result in the unit you chose, so you never have to do the division by hand.

What the numbers cannot do is diagnose you. A single panel is a snapshot, and cholesterol varies with illness, fasting, and lab error. Risk also depends on age, blood pressure, smoking, diabetes, and family history — a total of 200 means something different at 30 with no other risk factors than at 60 with high blood pressure. Use this calculator to understand your results and to prepare questions for your doctor, not as a substitute for medical advice.

Worked example

Your lab report shows total cholesterol 200 mg/dL, HDL 50 mg/dL, LDL 130 mg/dL, and triglycerides 150 mg/dL. What does the panel say?

Step 1: TC/HDL ratio — 200 ÷ 50 = 4.0, in the average range (under 3.5 is ideal, over 5.0 is higher risk).
Step 2: LDL/HDL ratio — 130 ÷ 50 = 2.6.
Step 3: Non-HDL cholesterol — 200 − 50 = 150 mg/dL, near optimal (under 130 is optimal).
Step 4: Categories — total cholesterol 200 is borderline high, LDL 130 is borderline high, HDL 50 is normal, and triglycerides 150 sit right on the borderline-high line.

The headline is mixed rather than alarming: nothing is in the high range, but three of the four measures sit at the borderline, and the ratio of 4.0 leaves room to improve — most often by raising HDL through regular exercise and, where it applies, quitting smoking and losing weight. Enter your own numbers above to see your panel.

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