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Glycemic Index Meal Calculator

See the overall glycemic impact of everything on your plate.

How it is calculated

You enter up to three foods, each with its glycemic index (GI, 0 to 110) and its carbohydrate in grams. The meal GI is the carb-weighted average: GI = (GI1×C1 + GI2×C2 + GI3×C3) ÷ (C1 + C2 + C3). The glycemic load is GL = GI × total carbs ÷ 100. The GI is shown as a whole number and the GL to one decimal. The category is based on the unrounded GI: up to 55 is Low, up to 69 Medium, above that High. Food 1 needs both values. Foods 2 and 3 are optional and ignored when left empty or at 0 g, but a carb amount for food 2 or 3 without its GI gives no result, as does any GI above 110, a negative value, or total carbs of 0.

Worked example

A plate has white rice (GI 73, 45 g carbs), lentils (GI 32, 15 g) and a salad dressing item (GI 15, 10 g). Total carbs = 45 + 15 + 10 = 70 g. Weighted sum = 73×45 + 32×15 + 15×10 = 3285 + 480 + 150 = 3915. Meal GI = 3915 ÷ 70 = 55.9, shown as 56, which is just over 55, so the category is Medium. Glycemic load = 55.9 × 70 ÷ 100 = 39.2.

Try this example →

Common mistakes

  • Entering the weight of the food instead of its carbohydrate in grams. The weighting and the load depend on grams of carbohydrate, not grams of food.
  • Typing a carb amount for food 2 or 3 and leaving its GI blank. The tool shows no result until the GI is filled in.
  • Averaging the GI values by hand. A food with 45 g of carbs counts far more than one with 10 g, so a simple average gives a wrong number.
  • Reading the category as a statement about the load. Low, Medium and High are based on the weighted GI alone; a Low-GI meal can still have a large glycemic load if the portion is big.
  • Entering a GI above 110, or a GI taken from a table made for a different reference food (bread instead of glucose). Values above 110 give no result, and mixed scales distort the average.

About this calculator

The glycemic index (GI) ranks individual carbohydrate-containing foods from 0 to 100 by how quickly they raise blood glucose relative to pure glucose, a scale developed by Dr. David Jenkins at the University of Toronto in 1981. A single food's GI, however, says nothing about a real plate of food that mixes several ingredients, so this calculator computes a carb-weighted average GI across the foods in a meal (up to three) — each food's GI is weighted by the share of total carbohydrate grams it contributes — and then derives the meal's glycemic load (GL), which factors in portion size (GL = GI × carbs in grams ÷ 100).

Dietitians and diabetes educators use meal-level GI and GL to explain why pairing a high-GI food like white rice with fiber, protein, or fat tends to blunt the overall blood-sugar spike, and endurance athletes use similar logic in reverse — favoring higher-GI carbs right before or during exercise for fast glucose availability, and lower-GI carbs beforehand for sustained energy.

Enter each food's carbohydrate content and known GI value and this calculator returns the meal's weighted GI along with its glycemic load, and classifies the meal's weighted GI as low (55 or below), medium (56 to 69) or high (70 or above).

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