Do “good” or “bad” ratio ranges appear in this calculator?

No. Reference ranges and clinical targets can vary and should come from your healthcare provider. This tool focuses on computing the ratios so you have accurate numbers to compare against the targets your clinician gives you.

Is the Friedewald formula always accurate?

The Friedewald formula is a widely used approximation but is less reliable when triglycerides are high, when samples are not fasting, or in certain medical conditions. When in doubt, rely on direct lab measurements and your clinician’s interpretation.

Should I change my medication based on these ratios?

No. Medication changes should only be made in consultation with a healthcare professional who has access to your full medical history and lab results.

Can I use this with SI units (mmol/L)?

This version assumes mg/dL, which is common in the US. If your lab reports in mmol/L, you would need to convert to mg/dL first or use a calculator designed for SI units.

How often should I recalculate these ratios?

Typically, you recalculate when you get new lab results. The frequency of testing should follow your clinician’s recommendations based on your risk profile and treatment plan.

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Cholesterol Ratio Calculator

Calculate total cholesterol plus key ratios (TC/HDL, LDL/HDL, TG/HDL) and fill in the missing value when possible.

Results

Total cholesterol: 190.00
LDL: 115.00
HDL: 55.00
Triglycerides: 100.00
Total cholesterol / HDL: 3.45
LDL / HDL: 2.09
Triglycerides / HDL: 1.82

How to use this calculator

Enter your total cholesterol, LDL, HDL, and triglyceride values from your lipid panel. Leave total or LDL blank only if your lab did not report it and you want an estimate.
We use the Friedewald formula to fill in a missing total or LDL value when possible, provided triglycerides are not excessively high.
With a complete set of values, we calculate total cholesterol/HDL, LDL/HDL, and triglycerides/HDL ratios.
Review the ratios as a numeric snapshot you can discuss with your healthcare provider or track over time.
Repeat the process with values from future lab tests to see how your ratios change with diet, exercise, or medication.

Inputs explained

Total cholesterol: Your measured total cholesterol level in mg/dL from a lab report. If your panel reports LDL, HDL, and triglycerides but not total cholesterol, you may leave this blank and let the Friedewald estimate fill it in.
LDL: Low-density lipoprotein cholesterol in mg/dL—often referred to as “bad” cholesterol because higher levels are associated with increased cardiovascular risk. You can leave this blank if your lab did not report it and total/HDL/TG are present.
HDL: High-density lipoprotein cholesterol in mg/dL—often called “good” cholesterol because higher levels are generally considered protective. HDL appears in the denominator of all three ratios.
Triglycerides: Triglyceride level in mg/dL. This value is used directly in the TG/HDL ratio and in the Friedewald estimates for total cholesterol and LDL when those are missing. Fasting levels are typically more reliable.

How it works

You can enter any combination of total cholesterol, LDL, HDL, and triglycerides from your lab report. All values are in mg/dL, which is the typical unit used in US labs.

If total cholesterol is left blank but LDL, HDL, and triglycerides (TG) are present, we estimate total using the Friedewald relationship: Total ≈ LDL + HDL + (TG ÷ 5).

If LDL is left blank but total cholesterol, HDL, and triglycerides are present, we estimate LDL as: LDL ≈ Total − HDL − (TG ÷ 5).

Once we have a full set of total, LDL, HDL, and triglycerides (either entered or estimated), we compute three key ratios: total cholesterol/HDL, LDL/HDL, and triglycerides/HDL. These ratios are unitless and can be compared over time or against reference ranges your clinician provides.

The Friedewald formula assumes a fasting sample and is generally considered unreliable when triglycerides are very high (often above ~400 mg/dL), so treat estimates in that range with extra caution and rely on direct lab values where available.

Formula

If Total is missing and LDL, HDL, and TG are present:\nTotal ≈ LDL + HDL + (Triglycerides ÷ 5)\n\nIf LDL is missing and Total, HDL, and TG are present:\nLDL ≈ Total − HDL − (Triglycerides ÷ 5)\n\nRatios (unitless):\nTC/HDL = Total cholesterol ÷ HDL\nLDL/HDL = LDL ÷ HDL\nTG/HDL = Triglycerides ÷ HDL

When to use it

Checking common cholesterol ratios from a recent lipid panel so you can see more than just isolated numbers.
Estimating total cholesterol or LDL using the Friedewald formula when only partial lipid values are printed on your lab summary.
Tracking how total/HDL, LDL/HDL, and triglycerides/HDL change over time as you adjust diet, exercise, or medications (under medical guidance).
Preparing for a doctor’s visit by turning raw lipid panel numbers into ratios that many clinicians use as quick risk markers.
Learning how different lab values interact—for example, how raising HDL or lowering triglycerides can change your ratios even if total cholesterol is stable.

Tips & cautions

Use lab results from a fasting test when possible; non-fasting triglycerides can be higher and may reduce the accuracy of Friedewald-based estimates.
The Friedewald formula is less accurate when triglycerides exceed roughly 400 mg/dL or in certain metabolic conditions; direct LDL measurements from your lab are preferred in those cases.
Ratios are just one piece of the cardiovascular risk puzzle. Blood pressure, blood sugar, family history, smoking status, and other factors are also important—discuss the full picture with your clinician.
Use the same laboratory (or reference ranges) when comparing results over time, as methods and reference intervals can vary between labs.
Not medical advice. Always discuss test results and ratios with a qualified healthcare professional before changing medications or treatment.
Uses a simplified Friedewald formula and does not account for all special cases (for example, very high triglycerides, non-fasting samples, or specific lipid disorders).
Does not incorporate other risk markers such as blood pressure, inflammatory markers, or imaging results; it focuses solely on cholesterol and triglyceride ratios.
Lab methodology differences and rounding may cause slight discrepancies between the calculator’s estimates and values on your official report.

Worked examples

Full panel with all values reported

Total cholesterol = 190 mg/dL, LDL = 115 mg/dL, HDL = 55 mg/dL, Triglycerides = 100 mg/dL.
TC/HDL ≈ 190 ÷ 55 ≈ 3.45.
LDL/HDL ≈ 115 ÷ 55 ≈ 2.09.
TG/HDL ≈ 100 ÷ 55 ≈ 1.82.
Interpretation: you now have concrete ratios to discuss with your clinician in addition to the raw numbers.

Estimating LDL when only total, HDL, and TG are known

Total cholesterol = 210 mg/dL, HDL = 50 mg/dL, Triglycerides = 150 mg/dL; LDL not reported.
Estimate LDL: LDL ≈ 210 − 50 − (150 ÷ 5) = 210 − 50 − 30 = 130 mg/dL.
Then compute ratios using the estimated LDL: TC/HDL = 210 ÷ 50 = 4.2; LDL/HDL ≈ 130 ÷ 50 = 2.6; TG/HDL = 150 ÷ 50 = 3.0.
Interpretation: use these as approximate values and confirm with your healthcare provider if precise LDL is clinically important.

Tracking improvement over time

Run the calculator with last year’s lipid panel to capture baseline ratios.
Run it again with this year’s panel after lifestyle changes or treatment.
Compare TC/HDL, LDL/HDL, and TG/HDL year over year to see whether trends are moving in the desired direction.

Deep dive

Calculate cholesterol ratios (total/HDL, LDL/HDL, triglycerides/HDL) and estimate missing total cholesterol or LDL using the Friedewald formula when appropriate.

Enter your lipid panel values to see key ratios that many clinicians use in cardiovascular risk discussions, and track how those ratios change over time.

Designed for patients and health-conscious users who want to turn raw cholesterol numbers into more intuitive ratios for conversations with their doctor.

FAQs

Do “good” or “bad” ratio ranges appear in this calculator?: No. Reference ranges and clinical targets can vary and should come from your healthcare provider. This tool focuses on computing the ratios so you have accurate numbers to compare against the targets your clinician gives you.
Is the Friedewald formula always accurate?: The Friedewald formula is a widely used approximation but is less reliable when triglycerides are high, when samples are not fasting, or in certain medical conditions. When in doubt, rely on direct lab measurements and your clinician’s interpretation.
Should I change my medication based on these ratios?: No. Medication changes should only be made in consultation with a healthcare professional who has access to your full medical history and lab results.
Can I use this with SI units (mmol/L)?: This version assumes mg/dL, which is common in the US. If your lab reports in mmol/L, you would need to convert to mg/dL first or use a calculator designed for SI units.
How often should I recalculate these ratios?: Typically, you recalculate when you get new lab results. The frequency of testing should follow your clinician’s recommendations based on your risk profile and treatment plan.

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This cholesterol ratio calculator is an educational tool that estimates total/HDL, LDL/HDL, and triglycerides/HDL ratios and may estimate missing total or LDL values using the Friedewald formula. It does not provide medical advice, diagnosis, or treatment and does not replace professional interpretation of lab work. Always consult a qualified healthcare professional for questions about your cholesterol results and cardiovascular risk.