Glycemic Load Calculator for Foods and Meals
Use this glycemic load calculator to turn the glycaemic index and carbohydrate of each food you enter into its glycemic load, and to total a meal or a day.
Work out glycemic load
Foods (example numbers shown; replace them with your own)
Enter the GI (0 to 110), the grams of carbohydrate in one serving and the servings you ate. Use available carbohydrate, as the formula specifies. The example rows are invented numbers for illustration, not published values.
This is arithmetic on the numbers you enter, not a prediction of anyone’s blood glucose. GI values come from tests in groups of people and vary with ripeness, cooking, what else is eaten and the person. People with diabetes should follow their clinician’s advice.
How the glycemic load calculator works
The glycemic load calculator multiplies each food’s glycaemic index by the carbohydrate in one serving and divides by 100. The Glycemic Index Foundation states the formula as “GL (grams) = GI ÷ 100 x available carbs (grams) per serving”:
GL per serving = GI × carbohydrate per serving (g) ÷ 100
GL for the amount eaten = GL per serving × servings eaten
share of an item = its GL eaten ÷ total GL × 100
Items are listed with the largest contribution first. Rows you leave completely blank are ignored. A row with a name or some values but a missing or invalid number is left out, named on screen, and the total is labelled “Subtotal (incomplete)”.
Worked example: a three-food meal
These are example numbers, not published values for any particular food:
| Food | GI | Carbs per serving | Servings | GL eaten | Share |
|---|---|---|---|---|---|
| Example food B | 70 | 20 g | 2 | 28 | 53.8% |
| Example food A | 50 | 30 g | 1 | 15 | 28.8% |
| Example food C | 40 | 15 g | 1.5 | 9 | 17.3% |
Food B gives 70 × 20 ÷ 100 = 14 per serving, so 2 servings give 28. The meal total is 52. The shares are rounded to one decimal place, so they add up to 99.9% rather than exactly 100%.
How do GI and glycemic load differ?
Glycaemic index describes a food, while glycemic load also reflects how much carbohydrate you actually eat. The Glycemic Index Foundation says GI is measured using a portion containing 50 grams of digestible (available) carbohydrate. A food with a high GI can have a small glycemic load if the serving has little carbohydrate, and the reverse can also be true. Entering the carbohydrate per serving is what lets the glycemic load calculator reflect your portion.
Which carbohydrate number should I enter?
Enter available carbohydrate, which is the wording the Glycemic Index Foundation uses in its formula. It describes the GI test portion as digestible (available) carbohydrate. The tool does not adjust anything: it uses exactly the number you type. If you use a different figure, such as the total carbohydrate on a label, your answer is on a different basis from the published formula, so say so if you share it.
Where do I look up a GI value?
Look up GI values in a published GI database or a trusted nutrition source, and enter the value you find. The glycemic load calculator does not contain a food list, so it cannot supply or check a GI for you. Values come from tests in groups of people and vary with ripeness, cooking, what else is eaten and the person. For background reading, our type 2 diabetes diet guide and our list of foods rich in fibre cover how carbohydrate fits into a wider eating pattern.
What this calculator does not tell you
- Blood glucose. It does not predict anyone’s blood glucose. It is arithmetic on the numbers you enter.
- Whether a food is good or bad for you. It does not label foods or set targets. A single number cannot judge a whole diet.
- Portion size in grams. To find the carbohydrate in your own portion, the nutrition label portion calculator can scale a label for you.
- Medical advice. People with diabetes should follow their clinician’s advice, and a doctor or registered dietitian can say how to use GI or GL in a personal plan.
Used with care and the right inputs, the glycemic load calculator is a quick way to compare servings and see which food contributes most to a meal total.
Sources for the formula
- Glycemic Index Foundation: Glycemic load (the formula using available carbohydrate per serving)
- Glycemic Index Foundation: About GI (GI measured using a portion containing 50 g of digestible, available carbohydrate)
Frequently Asked Questions
Multiply the food’s glycaemic index (GI) by the grams of available carbohydrate in one serving, then divide by 100. The Glycemic Index Foundation gives the formula as GL = GI ÷ 100 × available carbs (grams) per serving. For example, GI 70 and 20 g of carbohydrate gives 70 × 20 ÷ 100 = 14. Multiply by the servings eaten for the amount you had.
Glycaemic index is a value for a food, measured using a portion that contains 50 g of digestible (available) carbohydrate. Glycemic load also uses the amount of carbohydrate in the serving you actually eat, so the same GI gives a smaller GL for a small serving and a bigger one for a large serving. The calculator above shows GL for one serving and for the amount eaten.
Use available carbohydrate, which is what the Glycemic Index Foundation formula specifies. The foundation describes the GI test portion as digestible (available) carbohydrate. The tool uses whatever carbohydrate number you type in, so it will not correct a total-carbohydrate figure for you. If you enter a different figure, your result is on a different basis from the published formula.
GI values come from published testing, so look them up in a GI database or a trusted nutrition source rather than guessing. The calculator does not store GI values; you enter the one you found. GI is measured in groups of people and can differ with ripeness, cooking and what else is eaten, so treat a single number as a reference value, not a personal result.
No. The calculator only does arithmetic on the numbers you enter. It does not predict anyone’s blood glucose, which varies with the person, the food’s ripeness and preparation, and the rest of the meal. If you have diabetes, follow your clinician’s advice and ask a doctor or registered dietitian before changing your diet based on any number.