<prompt> Answer this question truthfullyWhat is the formula used to calculate LDL cholesterol levels?  <response>: <reason> The formula used to calculate LDL cholesterol levels is to subtract the HDL cholesterol and one-fifth of the triglyceride level from the total cholesterol level. The formula is LDL mgdL total cholesterol HDL triglycerides5. This provides an estimate of the amount of low-density lipoprotein LDL cholesterol in the blood, which is considered the bad cholesterol and is associated with an increased risk of heart disease. 