Cholesterol Ratio Calculator

Take your most recent lipid panel and find three lines: total cholesterol, HDL cholesterol and LDL cholesterol. Enter 180 in the total cholesterol field and 60 in the HDL field. LDL is optional; enter 100 if your report lists it.

The results panel shows a TC/HDL ratio of 3.0 with the band Low risk, and non-HDL cholesterol of 120 mg/dL. Because an LDL value was entered, it also shows an LDL/HDL ratio of 1.7 (100 ÷ 60 = 1.67, rounded to one decimal). Leave LDL at zero and that line simply disappears; nothing else changes, because LDL is not used in the ratio, the band or the non-HDL figure.

Use two numbers from the same blood draw. Pairing this year's total cholesterol with last year's HDL produces a ratio that describes neither test.

Enter values in mg/dL. If your laboratory reports mmol/L, multiply each cholesterol value by 38.67 first. The ratio itself is unitless, but the non-HDL line is labelled in mg/dL, and the function sets any HDL entry below 1 to 1 to avoid dividing by zero. A low HDL typed in mmol/L, such as 0.9, would therefore be silently changed to 1.0 and give the wrong ratio.

TC/HDL ratio = total cholesterol ÷ HDL cholesterol, shown to one decimal place.

Non-HDL cholesterol = total cholesterol − HDL cholesterol, shown as a whole number of mg/dL.

LDL/HDL ratio = LDL cholesterol ÷ HDL cholesterol, calculated only when LDL is greater than zero.

Band rule: a ratio below 3.5 is Low risk; a ratio from 3.5 up to and including 5.0 is Moderate risk; anything above 5.0 is Higher risk.

The band is decided on the unrounded ratio, which matters at the edges. Total cholesterol 175 with HDL 50 is exactly 3.5 and reads Moderate risk. Total cholesterol 173 with HDL 50 is 3.46: the screen shows 3.5, but the band is Low risk. Likewise 250 with HDL 50 is exactly 5.0 and stays Moderate, while 252 with HDL 50 is 5.04, displays as 5.0 and reads Higher risk. A result sitting on a boundary means the same thing on either side of it.

Where the bands come from: the ratio's value as a predictor was established in Framingham Heart Study analyses, summarised by Castelli and colleagues in Annals of Epidemiology (1992). The 3.5 and 5.0 cut points are a long-standing screening convention repeated in patient education material for decades. They are not treatment targets in NCEP ATP III (2001) or in the 2026 ACC/AHA Guideline on the Management of Dyslipidemia, which set goals for LDL and non-HDL cholesterol instead.

Enter total cholesterol 240, HDL 40 and LDL 160. The ratio is 6.0, in the Higher risk band; non-HDL cholesterol is 200 mg/dL; and the LDL/HDL ratio is 4.0.

Read against the NCEP ATP III categories (2001), each number tells part of the story. A total cholesterol of 240 mg/dL is the start of the high category, which begins at 240. An LDL of 160 falls in the high range of 160 to 189. An HDL of 40 sits right on the low-HDL line, which ATP III draws below 40 mg/dL.

The ratio is high because two things are wrong at once: more cholesterol overall and less HDL. Hold total cholesterol at 200 and change only HDL to see how much HDL moves the ratio. With HDL at 70 the ratio is 2.9 (Low risk); at 50 it is 4.0 (Moderate risk); at 35 it is 5.7 (Higher risk). Same total, three different bands. That is the one thing a ratio shows that a total cholesterol number alone cannot.

A standard lipid panel reports total cholesterol, HDL, triglycerides and LDL. Total cholesterol, HDL and triglycerides are measured directly. LDL is often calculated from the other three. The oldest method, the Friedewald equation (LDL = total cholesterol − HDL − triglycerides ÷ 5, in mg/dL), becomes unreliable when triglycerides are high and is not used at 400 mg/dL or above. The 2026 ACC/AHA dyslipidemia guideline prefers the Martin/Hopkins or Sampson/NIH equations over Friedewald for calculated LDL.

Fasting is no longer routine for most people. Both the 2018 AHA/ACC blood cholesterol guideline and its 2026 replacement accept a non-fasting sample for most adults. Fasting is most useful when earlier triglycerides were 400 mg/dL or higher, or when an inherited lipid disorder is suspected.

This matters for the calculator because its inputs are the stable part of the panel. Neither the ratio nor non-HDL cholesterol uses triglycerides or a calculated LDL, so a non-fasting result gives a usable ratio. The LDL/HDL ratio is the exception: if your LDL line was calculated from high triglycerides, that ratio inherits the error.

HDL is the one lipoprotein that is not a target. Everything else in total cholesterol, including LDL, VLDL, remnant particles and lipoprotein(a), can deposit cholesterol in artery walls. Subtracting HDL from the total counts all of it in one number, and it does not depend on an LDL estimate.

NCEP ATP III (2001) first made non-HDL cholesterol a secondary target, set 30 mg/dL above the LDL goal. The 2026 ACC/AHA Guideline on the Management of Dyslipidemia, published in March 2026 in Circulation and JACC, went further. It restored numeric goals for both LDL and non-HDL cholesterol. For people at borderline or intermediate 10-year risk, the non-HDL goal is below 130 mg/dL, alongside LDL below 100. At high risk it is below 100 mg/dL, alongside LDL below 70. For very-high-risk secondary prevention it is below 85 mg/dL, alongside LDL below 55. Which goal applies depends on a risk estimate and a clinician's judgement, not on this calculator.

A ratio can hide the absolute burden. Total cholesterol 260 with HDL 80 gives a ratio of 3.3, comfortably in the Low risk band, yet non-HDL cholesterol is 180 mg/dL, above every one of those goals. A high HDL makes the ratio look reassuring without removing any of the atherogenic cholesterol, which is why this calculator shows both numbers side by side.

This calculator does not diagnose anything and does not estimate cardiovascular risk. It divides and subtracts the numbers you enter. It ignores triglycerides, blood pressure, age, sex, smoking, diabetes, kidney disease, family history and lipoprotein(a), all of which change how a lipid result is read. The 2026 ACC/AHA guideline recommends measuring lipoprotein(a) at least once in adulthood, and no ratio can show it.

The risk bands are a screening convention, not guideline treatment thresholds. A low-risk ratio does not mean your LDL or non-HDL cholesterol is at goal, and a higher-risk ratio is not a reason to start or stop any medication.

The tool is built for adult values in mg/dL. Children and adolescents are assessed against different cut points, and lipid levels rise normally during pregnancy, so neither group should read these bands as written. Anyone with an LDL of 190 mg/dL or higher, a known inherited lipid disorder, or existing heart disease needs clinical care, not a ratio.

A ratio becomes a risk estimate only when it is combined with other factors, and the Framingham cardiac risk calculator does exactly that: it uses the same total and HDL cholesterol plus age, systolic blood pressure, smoking and diabetes to estimate ten-year cardiovascular risk. Blood pressure is the other routine number a clinician reads beside a lipid panel, and the blood pressure category calculator places a reading in the 2017 ACC/AHA categories. Body weight and where it sits affect lipids too. The BMI calculator gives the standard weight-for-height category, and the waist-to-height ratio calculator screens for central fat, which tends to travel with low HDL and high triglycerides. Because diabetes moves someone into a higher-risk group under cholesterol guidelines, the A1C to average blood sugar calculator is a useful companion if you have a recent A1C result.