Ketone Level Interpreter

A blood ketone meter measures β-hydroxybutyrate (BHB), the dominant ketone body circulating in your blood, in mmol/L. Ketones are the fuel your liver makes from fat when glucose and insulin are low — during a low-carbohydrate diet, fasting, or prolonged exercise. A higher BHB means your body is running more on fat-derived fuel and less on glucose at that moment.

This tool reads below 0.5 mmol/L as baseline (not in ketosis), 0.5 to 1.0 as light ketosis, 1.0 to 3.0 as nutritional ketosis — the target zone for most people on a ketogenic diet — and 3.0 to 5.0 as deep ketosis, typical of extended fasting or therapeutic protocols. A reading of 5.0 or above is a seek-review flag. There is no need to chase the highest number; the 1.0-to-3.0 band captures the state most keto goals aim for.

This is usually keto-adaptation, not a loss of ketosis. After about four to eight weeks, the body gets more efficient at using ketones for fuel — muscle and other tissues burn BHB rather than leaving it in the bloodstream — so blood levels often settle into the 0.5 to 1.5 range even when the diet has not changed. Lower circulating ketones in an adapted person reflect better utilization, not a diet that stopped working.

Nutritional ketosis is a controlled state and is different from diabetic ketoacidosis (DKA), a medical emergency in which ketones and blood sugar are both very high at once. The risk is concentrated in people with type 1 diabetes and users of SGLT2-inhibitor medications, who can develop DKA even at near-normal glucose. A reading of 5.0 mmol/L or above — especially with nausea, vomiting, rapid breathing, or confusion — warrants prompt medical attention.

Blood BHB is the gold standard for assessing current ketosis. Urine strips measure acetoacetate, a different ketone that becomes unreliable once you are keto-adapted because the body excretes less of it. Breath analyzers measure acetone and are reasonably good for trends but less precise than blood. To know your ketone level at a given moment, a fingerstick blood meter is the most reliable choice. Pair ketones with a blood glucose reading for the fuller fuel-state picture.