Use this Cholesterol Ratio Calculator to calculate common lipid-panel relationships from your blood test results. It can show total cholesterol to HDL ratio, LDL to HDL ratio, triglycerides to HDL ratio, non-HDL cholesterol, non-HDL to HDL ratio, and an estimated LDL value from standard lipid inputs.

Reviewed by: AjaxCalculators Editorial Team
Last updated: April 23, 2026
Method source: Standard lipid ratio arithmetic, non-HDL cholesterol calculation, and Friedewald estimated LDL formula
Editorial standards: AjaxCalculators Editorial Policy

What This Cholesterol Ratio Calculator Calculates

This calculator can show:

• Total cholesterol / HDL ratio
• LDL / HDL ratio
• Triglycerides / HDL ratio
• Non-HDL cholesterol
• Non-HDL / HDL ratio
• Estimated LDL (Friedewald)

It accepts lipid values in either mg/dL or mmol/L. Because ratios use the same unit in the numerator and denominator, the units cancel out for the ratio outputs.

How the Cholesterol Ratio Calculator Works

Total Cholesterol / HDL Ratio

TC / HDL ratio = total cholesterol ÷ HDL cholesterol

This ratio compares overall cholesterol with HDL (“good” cholesterol). Lower values are generally better.

LDL / HDL Ratio

LDL / HDL ratio = LDL cholesterol ÷ HDL cholesterol

This compares LDL (“bad” cholesterol) with HDL.

Triglycerides / HDL Ratio

TG / HDL ratio = triglycerides ÷ HDL cholesterol

This is another relationship often discussed when reviewing lipid patterns.

Non-HDL Cholesterol

Non-HDL cholesterol = total cholesterol − HDL cholesterol

Non-HDL includes LDL and other atherogenic cholesterol-containing particles. It is widely used in modern lipid interpretation because it captures more of the “bad” cholesterol burden than LDL alone.

Non-HDL / HDL Ratio

Non-HDL / HDL ratio = non-HDL cholesterol ÷ HDL cholesterol

Estimated LDL (Friedewald)

When triglycerides are available, LDL can be estimated in mg/dL using the classic Friedewald equation:

Estimated LDL = total cholesterol − HDL cholesterol − (triglycerides ÷ 5)

This is a common lab estimate, but it becomes unreliable when triglycerides are high.

Assumptions and Important Notes

• This calculator is for lipid-ratio arithmetic and educational review, not diagnosis.
• Lower lipid ratios are generally more favorable, but clinicians interpret them together with age, blood pressure, diabetes status, smoking, family history, and overall cardiovascular risk.
• Non-HDL cholesterol is often considered more useful than ratio alone for risk prediction.
• The Friedewald LDL estimate may be inaccurate when triglycerides are high, especially above 400 mg/dL.
• If your triglycerides are high or your result is clinically important, direct LDL measurement or a newer calculation method may be preferable.
• This page does not replace medical interpretation of a lipid panel.

Worked Example

Suppose a lipid panel shows:

• Total cholesterol: 200 mg/dL
• HDL: 50 mg/dL
• LDL: 120 mg/dL
• Triglycerides: 150 mg/dL

Step 1: Calculate TC / HDL ratio
200 ÷ 50 = 4.0

Step 2: Calculate LDL / HDL ratio
120 ÷ 50 = 2.4

Step 3: Calculate TG / HDL ratio
150 ÷ 50 = 3.0

Step 4: Calculate non-HDL cholesterol
200 − 50 = 150 mg/dL

Step 5: Calculate non-HDL / HDL ratio
150 ÷ 50 = 3.0

Step 6: Estimate LDL using Friedewald
200 − 50 − (150 ÷ 5) = 200 − 50 − 30 = 120 mg/dL

This example shows how one lipid panel can generate several related ratio views, but those numbers still need clinical context.

How to Use This Cholesterol Ratio Calculator

1. Enter your total cholesterol.
2. Enter your HDL cholesterol.
3. Enter your LDL cholesterol if available.
4. Enter your triglycerides.
5. Choose mg/dL or mmol/L for the input fields.
6. Click Calculate to see all ratios, non-HDL, and the estimated LDL output.

How to Interpret the Result

Total cholesterol / HDL ratio is one traditional risk marker. NHS-style public guidance commonly uses a healthy guide of below 6 for adults, but targets vary by overall risk profile.

Non-HDL cholesterol is especially useful because it includes more of the atherogenic cholesterol burden than LDL alone.

Estimated LDL should be treated cautiously if triglycerides are high, because Friedewald becomes less reliable in that setting.

If your lipid numbers are being used for treatment decisions, the most important interpretation is the one given by your clinician or lab report in context.

Practical Uses of a Cholesterol Ratio Calculator

• review multiple lipid ratios from one panel
• calculate non-HDL cholesterol quickly
• compare mg/dL and mmol/L entries without changing the ratio meaning
• double-check a Friedewald LDL estimate
• understand which lipid relationships may matter beyond total cholesterol alone

References

1. NHS: cholesterol levels, HDL, non-HDL, and how results are used with wider cardiovascular-risk assessment
2. NHS Wales: total cholesterol to HDL ratio guide and healthy-level overview
3. Mayo Clinic: non-HDL cholesterol may be more useful than cholesterol ratio alone
4. Bronson Laboratories: Friedewald equation loses accuracy when triglycerides are high
5. CDC NHANES: Friedewald equation is not valid for triglycerides greater than 400 mg/dL

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Disclaimer: This calculator is for educational use only. It does not diagnose high cholesterol, heart disease, or stroke risk. Seek clinician advice for abnormal results, very high triglycerides, or treatment decisions.