Cholesterol Calculator
Use this cholesterol calculator to find your LDL cholesterol and total-to-HDL ratio from a standard lipid panel.
Updated September 18, 2026
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How LDL Cholesterol Is Calculated
Most routine lipid panels measure total cholesterol, HDL, and triglycerides directly, but not LDL itself, LDL is usually calculated from the other three rather than measured separately, since direct LDL measurement is more expensive and not always necessary¹.
What This Calculator Measures
This calculates LDL cholesterol from your total cholesterol, HDL, and triglycerides, plus the total-to-HDL ratio, a commonly cited secondary way a lipid panel gets interpreted.
The Formula
LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5), in mg/dL
This is the Friedewald formula, developed in 1972 and still the most widely used method. It's invalid above roughly 400 mg/dL triglycerides and becomes progressively less accurate at high triglycerides or low LDL even below that threshold¹.
Cholesterol ratio = Total Cholesterol ÷ HDL
How This Calculator Computes Your Result
Enter your total cholesterol, HDL, and triglycerides. Below 400 mg/dL triglycerides, we calculate LDL using the Friedewald formula. Between 400 and 800 mg/dL, where Friedewald is known to break down, we switch automatically to the Sampson/NIH equation instead, still validated in that range and considerably more accurate than forcing Friedewald past its limit³. Above 800 mg/dL, even Sampson's own validation doesn't extend that far, so we flag the result rather than show a number neither formula can support. The cholesterol ratio is calculated directly regardless of triglyceride level.
Why Friedewald Isn't the Only Option Anymore
Friedewald's fixed ÷5 divisor was a reasonable approximation in 1972, but it doesn't hold up well across the full range of real-world triglyceride and LDL levels. The Martin/Hopkins method replaced that fixed divisor with one that varies based on the person's own triglyceride and non-HDL cholesterol levels, and was shown to outperform Friedewald, especially at high triglycerides or low LDL².
This calculator doesn't implement Martin/Hopkins directly, its full variable-factor table isn't published in an openly reusable form. Instead, above 400 mg/dL triglycerides, this calculator switches to the Sampson/NIH equation, a newer regression model validated up to 800 mg/dL, twice the range Friedewald can handle at all³.
Sampson LDL = TC ÷ 0.948 − HDL ÷ 0.971 − (TG ÷ 8.56 + (TG × non-HDL) ÷ 2140 − TG² ÷ 16100) − 9.44, in mg/dL
A Note on Accuracy
A calculated LDL is an estimate derived from other values, not a direct measurement, direct LDL testing is more accurate when precision matters clinically. The Sampson/NIH equation's own validation stops at 800 mg/dL triglycerides, above that level neither formula this calculator uses is reliable, and a direct LDL measurement is needed. Cholesterol values alone don't determine cardiovascular risk, they're one input among several used in real risk assessment.
Frequently Asked Questions
What happens between 400 and 800 mg/dL triglycerides?
Below 400 mg/dL triglycerides, using the Friedewald formula: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5), in mg/dL¹. Between 400 and 800 mg/dL, we switch automatically to the Sampson/NIH equation, which stays accurate in a range where Friedewald is known to break down³.
What happens if my triglycerides are extremely high?
At that point, even the Sampson/NIH equation is outside its own validated range³, so the calculator won't display a number from either formula. A direct LDL measurement is needed instead of any calculated estimate.
What is the total-to-HDL ratio?
Total Cholesterol ÷ HDL Cholesterol, a commonly cited secondary way a lipid panel gets interpreted alongside the individual values.
Does cholesterol alone determine my heart disease risk?
No. Cholesterol values are one input among several, including age, blood pressure, smoking status, diabetes, and family history, used in real cardiovascular risk assessment.
Sources
Estimation of the Concentration of Low-Density Lipoprotein Cholesterol in Plasma, Without Use of the Preparative Ultracentrifuge, Friedewald, Levy & Fredrickson, Clinical Chemistry, 1972
Comparison of a Novel Method vs the Friedewald Equation for Estimating Low-Density Lipoprotein Cholesterol Levels, Martin et al., JAMA, 2013
A New Equation for Calculation of Low-Density Lipoprotein Cholesterol in Patients With Normolipidemia and/or Hypertriglyceridemia, Sampson et al., JAMA Cardiology, 2020
Cholesterol Calculator
Use this cholesterol calculator to find your LDL cholesterol and total-to-HDL ratio from a standard lipid panel.
Updated September 18, 2026
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How LDL Cholesterol Is Calculated
Most routine lipid panels measure total cholesterol, HDL, and triglycerides directly, but not LDL itself, LDL is usually calculated from the other three rather than measured separately, since direct LDL measurement is more expensive and not always necessary¹.
What This Calculator Measures
This calculates LDL cholesterol from your total cholesterol, HDL, and triglycerides, plus the total-to-HDL ratio, a commonly cited secondary way a lipid panel gets interpreted.
The Formula
LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5), in mg/dL
This is the Friedewald formula, developed in 1972 and still the most widely used method. It's invalid above roughly 400 mg/dL triglycerides and becomes progressively less accurate at high triglycerides or low LDL even below that threshold¹.
Cholesterol ratio = Total Cholesterol ÷ HDL
How This Calculator Computes Your Result
Enter your total cholesterol, HDL, and triglycerides. Below 400 mg/dL triglycerides, we calculate LDL using the Friedewald formula. Between 400 and 800 mg/dL, where Friedewald is known to break down, we switch automatically to the Sampson/NIH equation instead, still validated in that range and considerably more accurate than forcing Friedewald past its limit³. Above 800 mg/dL, even Sampson's own validation doesn't extend that far, so we flag the result rather than show a number neither formula can support. The cholesterol ratio is calculated directly regardless of triglyceride level.
Why Friedewald Isn't the Only Option Anymore
Friedewald's fixed ÷5 divisor was a reasonable approximation in 1972, but it doesn't hold up well across the full range of real-world triglyceride and LDL levels. The Martin/Hopkins method replaced that fixed divisor with one that varies based on the person's own triglyceride and non-HDL cholesterol levels, and was shown to outperform Friedewald, especially at high triglycerides or low LDL².
This calculator doesn't implement Martin/Hopkins directly, its full variable-factor table isn't published in an openly reusable form. Instead, above 400 mg/dL triglycerides, this calculator switches to the Sampson/NIH equation, a newer regression model validated up to 800 mg/dL, twice the range Friedewald can handle at all³.
Sampson LDL = TC ÷ 0.948 − HDL ÷ 0.971 − (TG ÷ 8.56 + (TG × non-HDL) ÷ 2140 − TG² ÷ 16100) − 9.44, in mg/dL
A Note on Accuracy
A calculated LDL is an estimate derived from other values, not a direct measurement, direct LDL testing is more accurate when precision matters clinically. The Sampson/NIH equation's own validation stops at 800 mg/dL triglycerides, above that level neither formula this calculator uses is reliable, and a direct LDL measurement is needed. Cholesterol values alone don't determine cardiovascular risk, they're one input among several used in real risk assessment.
Frequently Asked Questions
What happens between 400 and 800 mg/dL triglycerides?
Below 400 mg/dL triglycerides, using the Friedewald formula: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5), in mg/dL¹. Between 400 and 800 mg/dL, we switch automatically to the Sampson/NIH equation, which stays accurate in a range where Friedewald is known to break down³.
What happens if my triglycerides are extremely high?
At that point, even the Sampson/NIH equation is outside its own validated range³, so the calculator won't display a number from either formula. A direct LDL measurement is needed instead of any calculated estimate.
What is the total-to-HDL ratio?
Total Cholesterol ÷ HDL Cholesterol, a commonly cited secondary way a lipid panel gets interpreted alongside the individual values.
Does cholesterol alone determine my heart disease risk?
No. Cholesterol values are one input among several, including age, blood pressure, smoking status, diabetes, and family history, used in real cardiovascular risk assessment.
Sources
Estimation of the Concentration of Low-Density Lipoprotein Cholesterol in Plasma, Without Use of the Preparative Ultracentrifuge, Friedewald, Levy & Fredrickson, Clinical Chemistry, 1972
Comparison of a Novel Method vs the Friedewald Equation for Estimating Low-Density Lipoprotein Cholesterol Levels, Martin et al., JAMA, 2013
A New Equation for Calculation of Low-Density Lipoprotein Cholesterol in Patients With Normolipidemia and/or Hypertriglyceridemia, Sampson et al., JAMA Cardiology, 2020
Cholesterol Calculator
Use this cholesterol calculator to find your LDL cholesterol and total-to-HDL ratio from a standard lipid panel.
Updated September 18, 2026
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How LDL Cholesterol Is Calculated
Most routine lipid panels measure total cholesterol, HDL, and triglycerides directly, but not LDL itself, LDL is usually calculated from the other three rather than measured separately, since direct LDL measurement is more expensive and not always necessary¹.
What This Calculator Measures
This calculates LDL cholesterol from your total cholesterol, HDL, and triglycerides, plus the total-to-HDL ratio, a commonly cited secondary way a lipid panel gets interpreted.
The Formula
LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5), in mg/dL
This is the Friedewald formula, developed in 1972 and still the most widely used method. It's invalid above roughly 400 mg/dL triglycerides and becomes progressively less accurate at high triglycerides or low LDL even below that threshold¹.
Cholesterol ratio = Total Cholesterol ÷ HDL
How This Calculator Computes Your Result
Enter your total cholesterol, HDL, and triglycerides. Below 400 mg/dL triglycerides, we calculate LDL using the Friedewald formula. Between 400 and 800 mg/dL, where Friedewald is known to break down, we switch automatically to the Sampson/NIH equation instead, still validated in that range and considerably more accurate than forcing Friedewald past its limit³. Above 800 mg/dL, even Sampson's own validation doesn't extend that far, so we flag the result rather than show a number neither formula can support. The cholesterol ratio is calculated directly regardless of triglyceride level.
Why Friedewald Isn't the Only Option Anymore
Friedewald's fixed ÷5 divisor was a reasonable approximation in 1972, but it doesn't hold up well across the full range of real-world triglyceride and LDL levels. The Martin/Hopkins method replaced that fixed divisor with one that varies based on the person's own triglyceride and non-HDL cholesterol levels, and was shown to outperform Friedewald, especially at high triglycerides or low LDL².
This calculator doesn't implement Martin/Hopkins directly, its full variable-factor table isn't published in an openly reusable form. Instead, above 400 mg/dL triglycerides, this calculator switches to the Sampson/NIH equation, a newer regression model validated up to 800 mg/dL, twice the range Friedewald can handle at all³.
Sampson LDL = TC ÷ 0.948 − HDL ÷ 0.971 − (TG ÷ 8.56 + (TG × non-HDL) ÷ 2140 − TG² ÷ 16100) − 9.44, in mg/dL
A Note on Accuracy
A calculated LDL is an estimate derived from other values, not a direct measurement, direct LDL testing is more accurate when precision matters clinically. The Sampson/NIH equation's own validation stops at 800 mg/dL triglycerides, above that level neither formula this calculator uses is reliable, and a direct LDL measurement is needed. Cholesterol values alone don't determine cardiovascular risk, they're one input among several used in real risk assessment.
Frequently Asked Questions
What happens between 400 and 800 mg/dL triglycerides?
Below 400 mg/dL triglycerides, using the Friedewald formula: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5), in mg/dL¹. Between 400 and 800 mg/dL, we switch automatically to the Sampson/NIH equation, which stays accurate in a range where Friedewald is known to break down³.
What happens if my triglycerides are extremely high?
At that point, even the Sampson/NIH equation is outside its own validated range³, so the calculator won't display a number from either formula. A direct LDL measurement is needed instead of any calculated estimate.
What is the total-to-HDL ratio?
Total Cholesterol ÷ HDL Cholesterol, a commonly cited secondary way a lipid panel gets interpreted alongside the individual values.
Does cholesterol alone determine my heart disease risk?
No. Cholesterol values are one input among several, including age, blood pressure, smoking status, diabetes, and family history, used in real cardiovascular risk assessment.
Sources
Estimation of the Concentration of Low-Density Lipoprotein Cholesterol in Plasma, Without Use of the Preparative Ultracentrifuge, Friedewald, Levy & Fredrickson, Clinical Chemistry, 1972
Comparison of a Novel Method vs the Friedewald Equation for Estimating Low-Density Lipoprotein Cholesterol Levels, Martin et al., JAMA, 2013
A New Equation for Calculation of Low-Density Lipoprotein Cholesterol in Patients With Normolipidemia and/or Hypertriglyceridemia, Sampson et al., JAMA Cardiology, 2020