Cholesterol Ratio Calculator

Calculate total-to-HDL first, then optionally add a full lipid panel. This is a supplementary screening summary, not a cardiovascular-risk score or diagnosis. Your values stay in your browser.

Enter your results

Units

Select the unit printed on your laboratory report. Switching units converts values already entered.

Use results from the same blood test. Mixing dates can produce misleading ratios.

Required
Required
Full lipid panel (optional)
Use laboratory-reported LDL when available. If blank, an estimate may be shown when triglycerides are supplied.
Adds TG/HDL, AIP and—if LDL is blank—a possible LDL estimate.

Estimated LDL: Friedewald: LDL = total − HDL − (TG ÷ 5) in mg/dL, or total − HDL − (TG ÷ 2.2) in mmol/L. It is less reliable as triglycerides rise and is not used here above 400 mg/dL (about 4.5 mmol/L).

Results

Total / HDL ratio
—
total cholesterol ÷ HDL
Enter total cholesterol and HDL.

Reference context: no universal stand-alone treatment target; use with absolute lipid values and overall cardiovascular risk.

Limitation: a lower ratio can still coexist with high LDL or non-HDL cholesterol.

Non-HDL cholesterol
—
total cholesterol − HDL
Enter total cholesterol and HDL.

Reference context: NHS healthy-adult guide <4.0 mmol/L. NICE secondary-prevention target ≤2.6 mmol/L applies to people with established CVD on treatment.

Limitation: personal targets differ by health history and overall risk.

A favorable ratio does not cancel a high LDL, triglyceride or non-HDL result. These calculations do not include age, blood pressure, smoking, diabetes or treatment, so they are not a QRISK, PREVENT or ASCVD risk assessment.

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Cholesterol ratio formulas

Total/HDLTotal/HDL = total cholesterol ÷ HDLUnitless when both use the same cholesterol unit.
LDL/HDLLDL/HDL = LDL cholesterol ÷ HDLUnitless when both use the same cholesterol unit.
TG/HDLTG/HDL = triglycerides ÷ HDLUnit-dependent because TG and cholesterol conversion factors differ.
Non-HDLNon-HDL = total cholesterol − HDLRetains the selected concentration unit.

Worked example: a complete lipid panel

For total cholesterol 200, HDL 50, LDL 120 and triglycerides 150 mg/dL:

  1. Total/HDL = 200 ÷ 50 = 4.00.
  2. LDL/HDL = 120 ÷ 50 = 2.40.
  3. TG/HDL = 150 ÷ 50 = 3.00 using mg/dL values.
  4. Non-HDL = 200 − 50 = 150 mg/dL.
  5. AIP first converts TG and HDL to mmol/L: log₁₀(1.69 ÷ 1.29) = 0.117.

How to interpret the results

Ratios compress several laboratory values into one summary. They can support a conversation, but current guidance emphasizes absolute LDL and non-HDL cholesterol and an overall risk assessment. The NHS cholesterol guide notes that clinicians combine cholesterol with factors such as age, blood pressure and health conditions; the 2026 AHA guideline similarly uses risk-based assessment.

NHS guide for healthy adults

  • Total cholesterol: below 5.0 mmol/L
  • HDL: above 1.0 mmol/L for men or 1.2 mmol/L for women
  • Non-HDL: below 4.0 mmol/L

These are general guides, not universal personal targets.

NICE secondary-prevention targets

For people with established cardiovascular disease taking lipid-lowering treatment: LDL ≤2.0 mmol/L or non-HDL ≤2.6 mmol/L.

These targets do not describe the general healthy-adult population.

Methodology and editorial information

Editorial owner: Starlight Tools Editorial Team Last updated: 18 July 2026 Clinical review: Not yet independently clinician-reviewed

The tool performs direct arithmetic in your browser. Cholesterol values convert at 38.67 mg/dL per mmol/L; triglycerides convert at 88.57 mg/dL per mmol/L. AIP uses the base-10 logarithm of the molar TG/HDL ratio described in the original AIP method. If LDL is absent, the optional Friedewald estimate is total − HDL − TG/5 in mg/dL or total − HDL − TG/2.2 in mmol/L.

LDL estimate limitation: laboratory-reported LDL is preferred. Friedewald accuracy declines as triglycerides rise, and newer equations may outperform it in some ranges. Consistent with the formula limitation described by the EAS/EFLM consensus, this calculator refuses to estimate above 400 mg/dL (approximately 4.5 mmol/L) and labels every estimate.

Common interpretation mistakes

  • Reading the ratio alone: a favorable ratio can coexist with high LDL, non-HDL or triglycerides.
  • Treating HDL as a treatment target: HDL contributes context, but raising HDL by itself is not the goal of this calculator or current lipid guidance.
  • Mixing tests or units: use all values from the same blood draw and select the unit printed on that report.
  • Treating research ratios as diagnoses: TG/HDL and AIP do not replace a clinician’s assessment or a validated cardiovascular-risk model.
  • Assuming estimated LDL is measured: check whether your laboratory reported LDL directly or calculated it.

Frequently asked questions

What is a good cholesterol ratio?

There is no single universal good ratio or treatment target. Total-to-HDL is a useful summary, but clinicians interpret it with LDL, non-HDL, triglycerides and your overall cardiovascular risk.

Is cholesterol ratio the same as total cholesterol?

No. Total cholesterol is a concentration in mg/dL or mmol/L. A cholesterol ratio divides one lipid result by another, such as total cholesterol divided by HDL.

Does age or sex change the ratio?

Age and sex do not change the arithmetic, but they can change how a clinician interprets the complete lipid panel and cardiovascular risk. This calculator does not estimate QRISK, PREVENT or another absolute-risk score.

Do I need to fast?

Routine lipid tests are often non-fasting. Follow your laboratory or clinician’s instructions; triglycerides can change after eating, and an unexpectedly high result may need a fasting repeat.

Can a good ratio hide high LDL?

Yes. A favorable-looking ratio does not cancel a high LDL, non-HDL or triglyceride result. Review every value from the lipid panel and your overall risk with a clinician.

Which cholesterol ratio should I use?

Total-to-HDL is usually what people mean by cholesterol ratio. LDL-to-HDL and triglyceride-to-HDL can add context, but current guidance gives greater weight to absolute LDL and non-HDL values plus overall cardiovascular risk.

Can I use mmol/L?

Yes. Select mmol/L before entering results, or switch units to convert values already entered. Total-to-HDL and LDL-to-HDL stay the same after conversion, but triglyceride-to-HDL changes because triglycerides use a different conversion factor.

What if LDL is missing?

Enter total cholesterol, HDL and triglycerides from the same test. The calculator can show a Friedewald LDL estimate when triglycerides are at or below 400 mg/dL (about 4.5 mmol/L), but a laboratory-reported LDL should be used when available.

Sources

For education only; not medical advice or a diagnosis. Seek prompt medical care for urgent symptoms. Discuss unexpected or markedly abnormal laboratory results with a qualified clinician.

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