Glucose Ketone Index (GKI) calculator

What is GKI?

The Glucose Ketone Index (GKI) is a numerical indicator that compares your blood glucose levels to your blood ketone levels. It provides insight into your current metabolic state — especially useful if you're aiming to enter or maintain ketosis. A lower GKI suggests deeper levels of ketosis, which may be helpful in certain therapeutic contexts, such as type 2 diabetes, neurological disorders, or cancer support protocols. Many people also track GKI during ketogenic diets to optimise fat-burning and metabolic health.

Your GKI score reflects how your body is balancing glucose and ketones. Generally speaking, a higher score suggests you're relying more on glucose, while a lower score means your body is primarily burning fat for energy.

A GKI above 9 means you're likely not in ketosis at all.Scores between 6 and 9 suggest low-level ketosis, possibly suitable for weight maintenance. A GKI between 3 and 6 indicates moderate, nutritional ketosis — the target for many people on a ketogenic diet. If your GKI is between 1 and 3, you're in a therapeutic range of ketosis, often targeted in clinical or therapeutic scenarios. A GKI below 1 signals very deep ketosis, which should only be pursued under medical guidance.

The GKI calculator is accurate as long as the inputs are correct and consistent. To use it, you’ll need your blood glucose and blood ketone readings, ideally both measured in mmol/L. If your glucose is in mg/dL, make sure to convert it to mmol/L before entering it. The formula used is simple:

GKI = Glucose (mmol/L) / Ketones (mmol/L)

For best results, test both glucose and ketones at the same time of day, preferably while fasting, to minimise variability. Always ensure your testing device is properly calibrated.

Lowering your GKI involves raising your ketone levels while keeping glucose levels steady or reduced. A ketogenic or very low-carbohydrate diet is one of the most effective ways to do this. You can also incorporate intermittent fasting, regular physical activity, and good sleep hygiene to support your body’s shift into fat-burning mode. If you're using GKI as part of a medical or therapeutic plan, always speak to your doctor or dietitian before making major changes.