Glycemic Load Calculator

Glycemic Load vs Glycemic Index

The Glycemic Index (GI) ranks carbohydrates on a scale of 0–100 based on how quickly they raise blood sugar, with pure glucose at 100. On its own it misleads, because it says nothing about how much of the food you actually eat.

Glycemic Load (GL) fixes this by combining both the GI and the actual carbohydrate content in a serving:

Formula:

GL = (GI × Available Carbs) / 100

Where:

• GI = Glycemic Index of the food (0–100)
• Available carbs = the carbohydrate that can be digested, which is total carbohydrate minus fiber
• Fiber is subtracted because it does not raise blood sugar

GL Classifications (per serving)

• Low GL: 10 or less
• Medium GL: 11 to 19
• High GL: 20 or more

There is no agreed daily GL “budget”. Figures like 80 or 100 a day circulate widely, but none comes from a guideline, so this page does not use one.

Read your label before subtracting fiber

On US and Canadian labels, “Total Carbohydrate” includes fiber, so you subtract it. On UK, EU, Australian and New Zealand labels the carbohydrate figure already leaves fiber out, and subtracting it a second time makes the load look smaller than it is. The label menu above handles both.

A Classic Example

Watermelon has a high GI of 76, but a typical 120g serving has only 6g of net carbs, giving a GL of just 5 (low). This shows why GI alone can be misleading for foods eaten in normal portions.

Where the preset numbers come from

The GI values in the food list are the averages in the International Tables of Glycemic Index and Glycemic Load (Atkinson, Foster-Powell and Brand-Miller, 2008). Brown rice is the one people are most often surprised by: boiled, it averages 68, not far below white rice at 73. Real foods vary a lot around these averages (variety, ripeness, cooking time, cooling), so treat them as a starting point.

Who Should Use This?

People managing type 1 or type 2 diabetes, pre-diabetes, or those following a low-glycemic diet will find GL tracking useful. Remember that fat and protein eaten with a carbohydrate slow its absorption, so a single food’s GL overstates its effect inside a mixed meal.