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LDL Calculator

Table of contents

The Friedewald equationHow to calculate LDL cholesterol?What's a normal LDL-C level?FAQs

The LDL calculator estimates the amount of low-density lipoproteins – complex particles that carry lipids in the blood. Their concentration is a very important parameter for predicting arteriosclerotic risk, but its direct measurement is not a part of the diagnostic routine. Instead, the patient's LDL is calculated and presented as LDL-C. It is universally accepted to use Friedewald equation to do so. Read on if you're curious about how to calculate LDL cholesterol.

After estimating your LDL blood level, check out our cholesterol ratio calculator to interpret the results.

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. If any health condition bothers you, consult a physician.

The Friedewald equation

The internationally recognized formula, developed by W.T. Friedewald, R.I. Levy, and D.S. Fredrickson in 1972, estimates the cholesterol content of the serum low-density lipoprotein fraction:

LDL = TC - HDL - 0.2 × TG

The values you need to insert in the equation are measurements from the standard cholesterol-focused blood test, called the lipid panel:

TC – total cholesterol – it's the sum of the concentration of all cholesterol particles, both the perceived "good" and "bad" ones. It should never exceed 200 mg/dL.

HDL – high-density lipoprotein – a.k.a. "the healthy cholesterol" is associated with lowering the build-up of plaque in the arteries in the process of atherosclerosis, which means it prevents cardiovascular disease and stroke. Its protective function is best when it's over 60 mg/dL. HDL shouldn't drop below 40 mg/dL.

TG – triglycerides – these transport glucose and lipids in both ways between liver and fatty tissue. Their high levels are related to an increased risk of atherosclerosis. Their level in a healthy person should be below 150 mg/dL.

The formula uses a coordinate of 0.2 for values in milligrams per deciliter (mg/dL). If your results are in millimoles per liter (mmol/L), use a coordinate of 0.45 or use our cholesterol units converter. You can switch the units in the calculator by clicking on their symbols.

How to calculate LDL cholesterol?

After having the lipid profile measured, you can start the calculation. Check what units your lab test results are expressed in – it's important for the calculation.

  1. Insert the total cholesterol level.
  2. Enter the high-density lipoprotein level.
  3. Fill in the third field with your triglyceride level.
  4. The calculated LDL cholesterol is presented in the last line.

What's a normal LDL-C level?

High levels of LDL promote the build-up of atherosclerotic tissue in the arteries. LDLs invade endothelium in the inner layer of the vessels and become oxidized by free radicals, which leads to the thickening and hardening of arterial walls.

According to the European Society of Cardiology (ESC) and the European
Atherosclerosis Society (EAS)
guidelines, the LDL-C level should be:

  • Below 115 mg/dL in people with low coronary risk (SCORE <5%);
  • Below 100 mg/dL in patients with medium coronary risk (SCORE 5%-10%); and
  • Below 70 mg/dL in patients with high coronary risk (SCORE >10%).

💡 SCORE stands for systematic coronary risk estimation.

Another calculator that might interest you is our VLDL cholesterol calculator.

FAQs

How do I calculate LDL with total cholesterol 230, HDL 47, and TG 123?

Your LDL cholesterol is equal to 158.4 mg/dL.
To calculate your LDL:

  1. Take your lipid profile results. You need TC - total cholesterol, HDL cholesterol, and TG - triglycerides.
  2. All the results must be in mg/dL.
  3. Use the Friedewald equation:
    LDL = TC - HDL - 0.2 × TG
  4. Plugging in the numbers:
    LDL = 230 - 47 - 0.2 × 123
    LDL = 230 - 47 - 24.6
    LDL = 158.4 (mg/dL)
  5. You can use our LDL calculator to check your results.

How do I calculate total cholesterol from LDL and HDL?

To estimate total cholesterol (TC):

  1. You need three values: LDL, HDL, and TG (triglycerides).
  2. All the values should be in mg/dL.
  3. Transform the Friedewald equation:
    LDL = TC - HDL - 0.2 × TG
    TC = LDL + HDL + 0.2 × TG
  4. Now plug in the numbers.
  5. Your total cholesterol result is ready!

How do I get my LDL below 70 mg/dL?

To lower your LDL cholesterol level:

  1. Your doctor might prescribe drugs. Take them as prescribed, usually every day.
  2. Quit smoking.
  3. Increase the soluble and insoluble fiber intake (eat oats, nuts, whole grains, pulses, vegetables, and fruit).
  4. Reduce the trans fats intake - preferably to zero. You'll find them in ready cakes and salty snacks.
  5. Minimize the saturated fatty acids intake. Leave off lard, butter, fatty meats, and cheese.
  6. Practice physical activity regularly.

Are there any Friedewald equation limitations?

There are limitations to the Friedewald equation. We can't use the formula if:

  1. The lipid profile test was taken non-fasting.
  2. The triglycerides (TG) level is over 400 mg/dL or below 100 mg/dL.
  3. The patient has type I or III hyperlipoproteinemia.
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