Glycaemic Load Calculator – Free Calculator

Understanding the glycaemic load calculator — concept and principle

Glycaemic load (GL) estimates how strongly a real serving of food is likely to raise blood glucose. It combines the glycaemic index (GI), which describes the type of carbohydrate, with the amount of carbohydrate you actually eat. It helps you plan meals and compare portion sizes.

GL weighs how fast a food raises blood sugar by how much carbohydrate you eat.

How it is calculated

GL = GI × available carbohydrate in the serving (g) ÷ 100.
Category: low if GL ≤ 10, medium if GL is above 10 and below 20, high if GL ≥ 20.

Available carbohydrate is the carbohydrate that is digested and absorbed as sugars, i.e. total carbohydrate minus dietary fibre. GI is a number on a scale where pure glucose is 100; GL has no unit.

The principle

GI is measured under standard conditions: volunteers eat a portion containing 50 g of available carbohydrate, and the rise in blood glucose over two hours (the area under the curve) is compared with the same amount of glucose. GI therefore describes quality but not quantity. Since the glucose response grows roughly with the amount of carbohydrate eaten, multiplying GI by the grams in your serving and dividing by 100 gives an estimate of the load, roughly in "grams of glucose equivalent".

Worked example

Inputs: GI 72, 30 g available carbohydrate in the serving.
GL = 72 × 30 ÷ 100 = 21.6.
Since 21.6 is at least 20, the category is high.
Halving the portion to 15 g of carbohydrate would give GL 10.8, which is medium.

Each point is the calculator re-run with only “Glycaemic index” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Glycaemic index	Glycaemic load
18	5.4
36	10.8
54	16.2
72	21.6
90	27
108	32.4
144	43.2

How to read the result

Where does your result fall?

For the GI itself, values of 55 or less are usually called low, 56–69 medium and 70 or more high. GL adds portion size: a food with a high GI but little carbohydrate per serving, such as watermelon, can have a low GL, while a large plate of a medium-GI food can have a high one. Adding protein, fat, fibre or acid to a meal often slows digestion and lowers the response. Use GL to compare options and portions, not as a precise prediction for one person.

Common mistakes

Using total carbohydrate including fibre instead of available carbohydrate.
Taking GI values from a different variety or cooking method; GI changes with ripeness, processing and cooking time.
Thinking a low GL means a food is healthy or low in calories.

Keep in mind: GI and GL are averages from small groups of healthy volunteers, and individual responses vary widely. This is not a diagnosis or treatment plan; people with diabetes should follow advice from their doctor or dietitian.

Frequently asked questions

Where can I find GI values?

The International Tables of Glycemic Index and Glycemic Load Values and the University of Sydney GI database list tested foods with their test conditions.

Is GL better than counting carbohydrates?

They answer different questions. Carbohydrate counting tracks the amount; GL also considers how quickly that carbohydrate raises glucose.

Does cooking pasta al dente change GI?

Yes, firmer pasta is typically digested more slowly and tends to have a lower GI than overcooked pasta.

Sources: Atkinson F.S., Foster-Powell K., Brand-Miller J.C., International Tables of Glycemic Index and Glycemic Load Values: 2008, Diabetes Care 31(12):2281–2283 · ISO 26642:2010, Food products — Determination of the glycaemic index (GI) and recommendation for food classification

Checked 8 Nov 2026. Typical coverage rates and standard formulas. Always check the product label and local building rules; buy 5–10% extra for waste.

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