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GKI Calculator (Glucose Ketone Index)

GKI is blood glucose in mmol/L divided by blood beta-hydroxybutyrate (BHB) in mmol/L. It is a research monitoring ratio, not a diagnosis, a weight-loss score, or a universal therapeutic target. This calculator checks the raw readings before it shows a ratio.

Adult scope: This calculator is for adults. For a child or teenager, use the pediatric diabetes or ketone plan from their care team. Seek emergency help for the warning symptoms below.

Read this before calculating

A home glucose or ketone reading cannot diagnose or exclude diabetic ketoacidosis (DKA), because it does not measure the metabolic acidosis required for diagnosis. Normal or lower glucose does not rule out DKA. Get emergency help now for repeated vomiting or inability to keep fluids down, abdominal pain while very unwell, rapid or deep breathing, confusion, or unusual sleepiness.

Glucose below 54 mg/dL (3.0 mmol/L) requires immediate action. Glucose at or above 600 mg/dL (33.3 mmol/L) meets the glucose criterion in the 2024 adult HHS consensus and requires emergency assessment. The calculator withholds GKI at either boundary.

Enter readings taken together

Blood glucose unit
Supported input: 20–600 mg/dL.
Supported input: 0.1–20 mmol/L, measured with a blood BHB meter.
Safety context

Select every statement that applies right now.

Safety check and result

No result yet. Enter both readings, complete the safety context, and select “Check readings and calculate.”

Formula, evidence, and limits

Formula: GKI = blood glucose (mmol/L) ÷ blood BHB (mmol/L). A glucose value in mg/dL is divided by 18.0182 before calculating the ratio. The readings should be taken at approximately the same time.

Meidenbauer, Mukherjee, and Seyfried proposed GKI in 2015 as a feasibility monitoring measure for metabolic management of brain cancer and called for further validation. That paper does not establish five universal zones or weight-loss targets. See the original GKI methodology paper.

Ratios can conceal the raw values. For example, 600 mg/dL glucose and 10 mmol/L BHB would arithmetically produce a GKI near 3.33, but this calculator withholds that ratio and prioritizes emergency assessment. The 2024 ADA/EASD/JBDS/AACE/DTS consensus defines DKA using diabetes or glucose criteria, ketones, and metabolic acidosis; it also recognizes euglycemic DKA. See the 2024 hyperglycemic-crises consensus report.

The calculator also withholds a ratio below 70 mg/dL (3.9 mmol/L). Below 54 mg/dL (3.0 mmol/L) is ADA level 2 hypoglycemia and requires immediate action. See the ADA Standards of Care in Diabetes—2026.

What this calculator cannot tell you

  • It cannot determine whether blood pH or bicarbonate is abnormal.
  • It cannot diagnose or exclude DKA or another medical condition.
  • It cannot determine a safe medication, diet, or fasting change.
  • It does not provide a validated target for weight loss.

For a neutral explanation of blood, breath, and urine measurements, see the ketone reading guide.

  • Ketone Reading Guide

    Check one blood, breath, or urine ketone reading before considering ratios.

  • What are ketones?

    Review ketone production, measurement, and clinical context.

  • All keto tools

    Compare the calculations, checkers, and planning tools available here.

Frequently asked questions

Is there a good GKI target for weight loss?
No universal GKI target has been validated for weight loss or general wellness. The ratio was proposed as a monitoring tool in brain-cancer metabolic-therapy research. If a clinical team has prescribed a ketogenic protocol, use only the target and testing schedule they provide.
Is a lower GKI always better?
No. A lower ratio can result from lower glucose, higher ketones, or both, and the same ratio can hide very different raw readings. It is not a score to minimize, and this calculator does not label GKI values as therapeutic zones.
Can GKI diagnose or rule out diabetic ketoacidosis?
No. DKA assessment requires the clinical context, ketones, and evidence of metabolic acidosis. A home GKI calculation does not measure blood pH or bicarbonate, so it cannot diagnose or exclude DKA. DKA can also occur without markedly high glucose, including with SGLT2-inhibitor use and during pregnancy.
Why might the calculator withhold the ratio?
Raw readings matter more than their quotient. The calculator withholds GKI when a reading or selected safety context needs prompt clinical attention, including glucose below 54 mg/dL or at or above 600 mg/dL, so an ordinary-looking ratio cannot mask a concerning raw value.
Can I use this GKI calculator for a child or teenager?
No. This page and its safety routes are scoped to adults and cite an adult hyperglycemic-crises consensus. Use the pediatric diabetes or ketone plan supplied by the child's care team, and seek emergency help for warning symptoms.