Lactate Unit Converter

In short Lactate is reported in mg/dL in some countries and mmol/L in others, and the two are related by a fixed factor: 1 mg/dL = 0.111015 mmol/L, so to go the other way you divide by 9.00779. 9 mg/dL is 1.0 mmol/L; 18 mg/dL is 2.0 mmol/L; 36 mg/dL is 4.0 mmol/L. The factor is not arbitrary — it comes from the molar mass, because lactic acid has a molar mass of 90.08 g/mol, and that is why every analyte has its own factor rather than one shared conversion. Lactate is unusual on this page in that mmol/L has won outside the United States even where conventional units are otherwise standard — endurance training talks about a 4 mmol/L threshold in every country. The factor is close to 9, so mg/dL divided by 9 is a good mental approximation. This converts units. It does not interpret results, does not compare your value against a reference interval, and is not a substitute for the clinician who ordered the test — reference intervals differ between laboratories, methods and populations.