Glucose Ketone Index (GKI): Calculator, Formula & GKI Chart

The Glucose Ketone Index (GKI) compares your blood glucose level with your blood ketone level to produce a single ratio. It is primarily used to track nutritional or therapeutic ketosis.

A lower GKI means ketones are higher relative to glucose, while a higher GKI means glucose is higher relative to ketones. However, lower does not automatically mean healthier or safer.

Key Takeaways

• GKI stands for Glucose Ketone Index and compares blood glucose with blood beta-hydroxybutyrate.
• The formula is glucose (mmol/L) ÷ ketones (mmol/L).
• If glucose is measured in mg/dL, divide it by approximately 18 before calculating GKI.
• A lower GKI means more ketones relative to glucose, but lower is not automatically better.
• There is no universally established ideal GKI for everyone.
• GKI is primarily a tracking metric, not a diagnostic test or complete measure of metabolic health.
• GKI cannot diagnose or rule out diabetic ketoacidosis (DKA).

GKI Chart: What Does Your GKI Mean?

GKI values are often grouped into ranges online, but these ranges should be interpreted cautiously. There are currently no universally validated clinical GKI targets for general health, diabetes management, or disease prevention.

GKI	What the Number Generally Indicates
Below 1	Very high ketones relative to glucose
1–3	High ketones relative to glucose
3–6	Moderate ketones relative to glucose
6–9	Lower ketones relative to glucose
Above 9	Relatively little ketosis compared with glucose

These ranges describe the relationship between glucose and ketones, not whether a result is medically good or bad.

Very low GKI values have primarily been investigated in therapeutic ketogenic research. More recent research has proposed broader uses for GKI, but disease-specific targets and clinical benefits still require further validation.²

Do not try to achieve the lowest possible GKI unless you are following a medically supervised treatment plan that specifically calls for it.

How to Calculate GKI

You need two blood measurements taken at approximately the same time:

1. Measure your blood glucose.
2. Measure your blood beta-hydroxybutyrate (BHB).
3. Convert glucose from mg/dL to mmol/L if necessary.
4. Divide glucose in mmol/L by ketones in mmol/L.

Calculation Example

Why Measure Glucose and Ketones Together?

Blood glucose shows how much glucose is circulating in your blood. If you want to compare a reading with common fasting and post-meal ranges, see our Blood Sugar Charts. Blood beta-hydroxybutyrate measures one of the main ketone bodies produced as the body increasingly relies on fat-derived fuel.

GKI combines those measurements into one ratio.

This can provide additional context when monitoring nutritional ketosis or a medically supervised ketogenic therapy. It may also make it easier to compare changes over time than looking at glucose or ketones alone.

However, GKI should not be considered a comprehensive measure of metabolic health. Glucose and ketones can change with meals, fasting, exercise, illness, stress, medications, and other factors.

What Is a Good GKI?

There is no single GKI that is ideal for everyone.

The appropriate range depends largely on why GKI is being measured. Someone tracking nutritional ketosis does not necessarily need the very low GKI sometimes discussed in research involving therapeutic ketogenic interventions.

The original GKI research focused on ketogenic metabolic therapy for brain cancer.¹ Research published in 2026 proposed studying GKI more broadly as a metabolic biomarker, but researchers have also emphasized that these applications and thresholds require further clinical validation.²

Instead of asking, “How low can I get my GKI?”, consider why you are measuring it and whether GKI is useful for that particular goal.

GKI and Diabetes: An Important Safety Difference

People with diabetes need to distinguish nutritional ketosis from diabetic ketoacidosis (DKA).

Nutritional ketosis can occur when carbohydrate intake is reduced and ketone production increases while sufficient insulin remains available.

DKA is very different. It develops in the setting of insufficient insulin and involves excessive ketone production and metabolic acidosis. It is a potentially life-threatening medical emergency.³

Can This Ratio Detect DKA?

No. GKI cannot diagnose or rule out diabetic ketoacidosis.

This is especially important because GKI is only a ratio. It does not measure blood acidity, and looking at the ratio alone can obscure an elevated ketone measurement.

Current criteria for DKA consider:

• diabetes or hyperglycemia;
• elevated ketones; and
• metabolic acidosis.³

DKA can also occur without severe hyperglycemia. This is known as euglycemic DKA and can occur in circumstances including SGLT2 inhibitor use.³

If you have diabetes, evaluate an elevated ketone reading separately rather than relying on your GKI.

If elevated ketones occur with symptoms such as nausea, vomiting, abdominal pain, rapid or deep breathing, dehydration, confusion, or illness, follow your diabetes sick-day plan and seek medical guidance as appropriate.

GKI vs. Ketone Level: What’s the Difference?

A blood ketone reading measures the concentration of beta-hydroxybutyrate in your blood.

GKI compares that ketone concentration with your glucose level.

For example:

Person A
Glucose: 90 mg/dL (5.0 mmol/L)
Ketones: 1.0 mmol/L
GKI: 5

Person B
Glucose: 144 mg/dL (8.0 mmol/L)
Ketones: 1.0 mmol/L
GKI: 8

Both have identical ketone levels, but their glucose-to-ketone ratios are different.

That is the primary information GKI adds beyond measuring ketones alone.

When Should You Measure It?

If you track GKI over time, consistent testing conditions make comparisons more meaningful.

Try to measure glucose and ketones:

• at approximately the same time of day;
• under similar fasting or post-meal conditions; and
• consistently in relation to exercise.

Meals, fasting, physical activity, stress, illness, and medications can influence glucose or ketone levels.

There is no established requirement for most people to check GKI every day. How often you measure it should depend on why you are tracking it and, when applicable, guidance from your healthcare team.

Does a Lower GKI Mean Better Health?

Not necessarily.

A lower GKI simply means ketones are higher relative to glucose.

It does not automatically indicate better glucose control, faster weight loss, lower disease risk, or better overall health. For a broader measure of long-term glucose exposure, the A1C Calculator can convert an A1C result to estimated average glucose.

Although researchers are investigating GKI as a potential metabolic biomarker, its broader clinical applications and optimal targets have not yet been established.²

For people with diabetes, glucose and ketone readings should also be evaluated individually rather than relying only on their ratio.

Can You Calculate GKI With Urine Ketones?

No. GKI should be calculated using blood beta-hydroxybutyrate rather than substituting a urine ketone result.

Urine ketone tests primarily detect acetoacetate, while blood ketone meters can directly measure beta-hydroxybutyrate.

This distinction is particularly important for people with diabetes. Laboratory guidance recommends specific blood beta-hydroxybutyrate measurement for diagnosing DKA and allows it to be used for monitoring DKA treatment.⁴

Frequently Asked Questions

Explore more Diabetes Calculators and Health Tools for blood sugar, nutrition, insulin, and other diabetes-related calculations.

References

1. Meidenbauer JJ, Mukherjee P, Seyfried TN. “The glucose ketone index calculator: a simple tool to monitor therapeutic efficacy for metabolic management of brain cancer.” Nutrition & Metabolism. 2015;12:12. [↩]
2. Lee DC, Duraj T, Cooper ID, et al. “The glucose ketone index: a proposed quantitative biomarker to support cancer and chronic disease prevention and management.” Frontiers in Science. 2026;4:1763395. [↩] [↩] [↩]
3. American Diabetes Association Professional Practice Committee for Diabetes. “16. Diabetes Care in the Hospital: Standards of Care in Diabetes—2026.” Diabetes Care. 2026;49(Suppl. 1):S339–S355. [↩] [↩] [↩]
4. Sacks DB, Arnold M, Bakris GL, et al. “Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus.” Diabetes Care. 2023;46(10):e151–e199. [↩]