Estimate glycemic load for one serving from glycemic index and available carbohydrate.
Serving values
Enter GI and carbohydrate
GL
Food summary
Per-serving glycemic load
The glycemic load will appear here
Use carbohydrate for the serving actually eaten, not necessarily the value per 100 grams.
Glycemic loadGL = glycemic index × carbohydrate grams ÷ 100
Glycemic load
0
Page category
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Carbohydrate used
0 g
Glycemic index
0
Educational estimate only. It is not medical advice, a diagnosis, or a substitute for assessment by a qualified healthcare professional. Glycemic responses vary among people and meals; this estimate is not a glucose-management plan.
Glycemic load combines a food’s index with the amount of carbohydrate in the chosen serving.
What is Glycemic Load?
Glycemic load (GL) puts two pieces of information together: how quickly a carbohydrate food tends to raise blood glucose and how much available carbohydrate is actually present in the portion. Glycemic index (GI) supplies the first part; carbohydrate grams supply the second. That makes GL more useful than GI alone when comparing ordinary servings. A watermelon and a dense cereal can have similar GI values while delivering very different amounts of carbohydrate per portion.
This calculator works with one food or one clearly defined serving at a time. It is useful for checking a label, comparing portion sizes, or understanding a published GL value. It does not predict an individual glucose reading. Preparation, ripeness, mixed meals, medication, activity and a person’s metabolism can all change the real response.
How to Use This Calculator
Enter the food’s published glycemic index on the 0–100 glucose scale. Then enter the grams of available carbohydrate in the portion you plan to eat. Available carbohydrate generally means carbohydrate that is digested and absorbed; it is not automatically the same as the “total carbohydrate” line on every label. If a reliable source reports milligrams, select mg and the calculator converts that amount to grams, although food portions are normally stated in grams.
Match the GI value to the same food and preparation method. Rolled oats, instant oats and steel-cut oats should not be treated as interchangeable.
Work out the available carbohydrate in the actual portion. If a label gives values per 100 g, scale them to the serving first.
Select the correct carbohydrate unit and calculate. The page multiplies GI by carbohydrate grams and divides by 100.
Read the low, medium or high label as a conventional description of that serving, then keep the numeric GL for comparisons.
When several carbohydrate foods are eaten together, calculating each item separately and adding the results can provide a rough meal total. That shortcut still cannot account fully for fat, protein, acidity, cooking and interactions among foods.
Formula Used
GL = GI × available carbohydrate in the serving (g) ÷ 100
The page describes a result of 10 or less as low, a result above 10 but below 20 as medium, and a result of 20 or more as high. These are descriptive bands commonly used in GI education. They are properties of the chosen portion, not blood-glucose targets or diagnoses. If carbohydrate is entered in milligrams, the calculator first uses grams = milligrams ÷ 1,000.
Variables Explained
Entry or result
Meaning
Practical check
Glycemic index (GI)
A relative ranking, usually measured against glucose = 100, of the blood-glucose response to a fixed amount of available carbohydrate.
Use a tested value for the same food, variety and preparation; do not guess from sweetness.
Available carbohydrate
The digestible carbohydrate in the portion, entered in grams or milligrams.
Scale the nutrition information to the portion and check how the source defines carbohydrate and fibre.
Glycemic load
The GI adjusted for the carbohydrate quantity in that serving.
Keep the number with its serving size; changing the portion changes GL.
Category
Low (≤10), medium (>10 and <20), or high (≥20) for the entered portion.
Use the band for description rather than as a personal treatment threshold.
Worked Example
Suppose a serving has a GI of 55 and contains 18 g of available carbohydrate. The calculation is 55 × 18 ÷ 100 = 9.9. The calculator displays 9.9, low glycemic load. Doubling that same serving to 36 g carbohydrate gives 55 × 36 ÷ 100 = 19.8, which falls in the medium band. The food’s GI did not change; the larger portion changed the load.
For a unit check, 18,000 mg converts to 18 g and therefore produces the same 9.9 result. Entering 18 with “mg” selected would mean only 0.018 g and return 0.01 after rounding, an implausibly small food portion. This is why the unit selector matters.
Why Use This Calculator?
GL is most helpful as a comparison. A lower number means the entered serving combines a lower GI, fewer available carbohydrate grams, or both. It does not mean a food is automatically nutritious, nor does a high number make a food forbidden. Fibre, protein, micronutrients, overall dietary pattern and portion context still matter.
People can have different post-meal glucose responses to the same food. GI values are averages from controlled testing and show natural variation. A home glucose meter or continuous glucose monitor measures a person at a particular time; GL is a food-based estimate. Anyone adjusting food because of diabetes, pregnancy, hypoglycaemia or glucose-lowering medicine should use a plan agreed with a qualified clinician or dietitian rather than changing treatment from this result.
Common Mistakes
Using the weight of the whole food as carbohydrate grams. A 150 g apple does not contain 150 g available carbohydrate.
Taking GI from a different variety or preparation. Processing and cooking can change starch availability.
Using total carbohydrate without checking how fibre is reported in the country or database.
Comparing GL figures that refer to different serving sizes.
Assuming “low GL” means unlimited portions or guarantees a small personal glucose rise.
Entering grams while mg is selected, or copying a per-100-g value without scaling it to the portion.
Frequently Asked Questions
Does glycemic load tell me what my blood glucose will be?
No. It summarizes a food and portion using population GI data. Your starting glucose, insulin response, activity, meal composition, medication and many other factors influence the reading you may see.
Should I use total carbohydrate or net carbohydrate?
Use the available carbohydrate definition paired with the GI source. Label rules differ by country, especially for fibre and sugar alcohols, so simply subtracting every fibre number can be wrong.
Can a high-GI food have a low glycemic load?
Yes. If a normal portion contains little available carbohydrate, its GL can be low despite a high GI. The numeric result must always be kept with the serving size.
How do I estimate the glycemic load of a meal?
Calculate the approximate GL of each carbohydrate-containing item using its own GI and serving carbohydrate, then add them. Treat the total as a rough estimate because mixed-meal effects are not fully represented.
Why does changing only the portion change the category?
GI stays fixed in this equation, while carbohydrate grams increase or decrease with the portion. Twice the carbohydrate produces twice the calculated GL.
Is a low glycemic load the same as low carbohydrate?
No. GL depends on both GI and carbohydrate quantity. A moderate amount of a low-GI carbohydrate and a small amount of a high-GI carbohydrate can produce similar loads.
Where should I get a GI value?
Use a tested database or published study that identifies the food and preparation. Marketing claims and estimates based only on taste are poor substitutes for measured GI data.
