Glycemic load calculator

What the number means

Two foods can raise blood glucose very differently even when they contain the same amount of sugar and starch. The glycemic index (GI) ranks the carbohydrate itself: it compares how fast equal amounts of carbohydrate from different foods lift blood glucose. It says nothing about portion size. A food can have a high index and still contribute little, because a normal serving holds very little carbohydrate. Glycemic load fixes that by combining quality and quantity in one number, which the University of Sydney describes as the amount of carbohydrate adjusted for its glycemic potency.

What is glycemic load?

Glycemic load (GL) is the glycemic index of a food multiplied by the grams of available carbohydrate in the portion, divided by 100. The index says how fast a carbohydrate raises blood glucose; the load adds how much of it you actually eat. A small baked potato (GI 80) with 15 g of carbohydrate has a load of 12.

What counts as a low, medium or high glycemic load?

For one serving, Harvard's Nutrition Source and the Oregon State Linus Pauling Institute give: 10 or under is low, 11 to 19 is medium and 20 or more is high. Both say "in general", so treat the lines as rough. This page calls a value above 10 and below 20 medium, so 10.5 is medium.

Where do I find the glycemic index of a food?

The University of Sydney's database at glycemicindex.com lists thousands of measured foods, and a packaged food may print its own value. We do not copy the database into this page, because it is the university's work and we have not checked its reuse terms; look the food up there and type the GI into the card. Values marked with a hash there come from studies that deviated from the ISO 26642:2010 method or varied widely.

What is the difference between GI and GL?

GI compares equal amounts of carbohydrate: it ranks foods as low (55 or less), medium (56 to 69) or high (70 or more). GL accounts for the portion. Watermelon has a high GI but little carbohydrate in a serving, so its load is low; the Linus Pauling Institute lists one serving of watermelon at 8 and a medium doughnut at 17 although both have a GI near 76.

Can I add up the glycemic load of a whole day?

Yes, the dietary GL is defined as the sum of the loads of all foods eaten, and this calculator adds them. We do not label the daily total as good or bad: we did not find a daily cut-off that Harvard, the Linus Pauling Institute or the University of Sydney publish, and some web charts give numbers without a source.

Is a low glycemic load always healthier?

No. The load says nothing about fiber, fat, protein, vitamins or calories, and a low-load food can be a poor choice for other reasons. Harvard also notes that the link between glycemic index and body weight is less well studied and remains controversial, and that associations with disease are associations, not proof.

Does this help with diabetes?

It can help you compare foods, but it is not a dosing tool and not medical advice. A calculated number does not replace your meter, your care team's plan or your own measured response. If you take insulin or other glucose-lowering medicine, follow the plan your clinician gave you.

How the calculation works

For each food the calculator takes the total carbohydrate printed on the label for one serving, subtracts the fiber, and treats the rest as available carbohydrate. It multiplies that by the GI and divides by 100: GL = GI × available carbohydrate (g) ÷ 100. The per-serving load is compared with the bands, and then multiplied by the number of servings you ate. The daily figure is the sum of those products. If you already know the available carbohydrate per serving, enter it as the carbohydrate and leave fiber at zero. The subtraction of fiber is our shortcut: the published definition uses available carbohydrate, and the label does not subtract sugar alcohols or resistant starch for you.

The GI bands that go with the index are those of the University of Sydney: low is 55 or less, medium 56 to 69, and high 70 or more.

Worked example

The University of Sydney's own FAQ uses two foods with 15 g of carbohydrate each. An apple has a GI of 40, so its load is 40 × 15 ÷ 100 = 6, which is low. A small baked potato has a GI of 80, so its load is 80 × 15 ÷ 100 = 12, which is medium and twice the apple's, although it is the same amount of carbohydrate. Eaten on the same day they add up to 18. Now a package case: a snack lists 36 g of total carbohydrate and 4 g of fiber per serving and its GI is 62. Available carbohydrate is 32 g, so one serving has a load of 62 × 32 ÷ 100 = 19.8 (medium), and two servings add 39.7 to the day.

Limits of this method

• Mixed meals. The Linus Pauling Institute warns that a meal GI calculated from single-food values is unlikely to predict the blood glucose response accurately, because fat, protein and fiber change how each food acts; it cites one study in which estimates from published values overshot direct measurements by 22 to 50 percent. Treat the daily total as a rough guide for comparing choices, not a prediction of your glucose curve.
• One food, many values. Variety, ripeness, processing and cooking all change the GI, and individual factors such as metabolic status and how thoroughly food is chewed may change the response. Two databases can list different numbers for what looks like the same food, and the University of Sydney marks values from studies that deviated from its ISO 26642:2010 method.
• The bands are approximate. Harvard words them as "in general", and the published lines leave gaps between 10 and 11 and between 19 and 20. Our rule for those gaps is stated above.
• It is not a nutrition score. A low load does not make a food healthy, and the evidence on weight is described by Harvard as less well studied and controversial.

Sources and related calculators

Sources, read October 28, 2026: University of Sydney, glycemicindex.com/faqs (formula, apple and baked potato examples, GI bands) and the GI search page; Harvard T.H. Chan School of Public Health, The Nutrition Source, “Carbohydrates and Blood Sugar” (GL bands); Oregon State University Linus Pauling Institute, “Glycemic Index and Glycemic Load” (formula, watermelon and doughnut examples, mixed-meal caveat). This page is not endorsed by or affiliated with these institutions. Related: macro calculator, calorie calculator, fiber intake calculator and added sugar calculator.

For general information only — not medical advice. Talk with your doctor or another health professional about your own health. How we check our calculators.