About GlucoMath
GlucoMath is a free set of blood sugar and glycemic calculators: glycemic load, glycemic index lookup, GMI, A1C ⇄ average glucose conversion, and mg/dL ⇄ mmol/L unit conversion. It is built for people who want to understand the numbers on their meter, CGM, or lab report — for educational purposes, not as a medical device. This page explains where every number on the site comes from.
Data
Where the GI data comes from
The food search and reference tables use the DiOGenes GI Database (diogenes-eu.org), created by the pan-European DiOGenes project and described in Aston et al., Obesity Reviews 2010. The project has ended and the database is no longer maintained or available online; this site uses its archived data.
These GI values are category-level assignments: foods were grouped into categories and each category was given a representative GI value. They are reference values, not individually measured results for every food in the list. The GI of a specific product can differ from its category value with variety, ripeness, processing, and preparation.
If a precise value matters to you, cross-check it against a maintained source such as the University of Sydney GI database or the international tables of glycemic index and glycemic load values (Atkinson et al., 2021). Migrating this site's data to the Atkinson 2021 international tables is the planned upgrade path.
Formulas
Formula sources
- Glycemic load: GL = GI × available carbohydrate (g) ÷ 100 — the standard definition of glycemic load per serving.
- A1C to eAG: eAG (mg/dL) = 28.7 × A1C − 46.7, from the ADAG study (Nathan et al., Diabetes Care 2008). The average-glucose-to-A1C estimator inverts this equation algebraically and therefore reports a range, not a single value.
- GMI: GMI (%) = 3.31 + 0.02392 × mean glucose (mg/dL), from Bergenstal et al., Diabetes Care 2018.
- Unit conversion: mmol/L = mg/dL ÷ 18.018, from the molar mass of glucose (about 180.18 g/mol).
Open source
Open-source attribution
GlucoMath is based on the open-source project glcalc.com by Assaf Morami, MIT License, © 2018. This site is a modified version of that project; the original copyright and permission notice is preserved in this repository's LICENSE file, as the MIT License requires.
Contact
Maintainer and contact
Maintained by the GlucoMath project. Questions, corrections, and data issues are welcome via GitHub Issues.
This tool has not been reviewed by a medical professional. Sources are cited above so you can verify every formula and data point yourself.
Disclaimer
Medical disclaimer
Everything on this site is provided for educational and informational purposes only. It is not medical advice and is not a substitute for professional medical advice, diagnosis, or treatment. The calculators apply published population-level formulas; your individual results can differ from any estimate shown here.
Diagnosing diabetes or prediabetes requires laboratory testing using an NGSP-certified method, ordered and interpreted by a healthcare professional. Never make treatment or medication changes based on this site's output alone — always talk to your doctor or diabetes care team first.