Glycemic Index Calculator
Look up GI values, calculate glycemic load per serving, and track your meal's total glycemic impact
Choose a food group to browse available foods
Select a food to auto-fill its GI and carbohydrate values
Enter the amount you plan to eat. The glycemic load will update automatically.
Use Net Carbs
Net carbs = Total carbs minus fiber. Preferred by low-carb practitioners.
Calculate GI & GL
Select a food category and item above, then click Calculate to see glycemic index, glycemic load, and blood sugar impact.
Meal Tracker
No foods added yet. Use the Add to Meal button to build your meal.
How to Use the Glycemic Index Calculator
Select a Food Category and Item
Choose a food category from the dropdown (such as Fruits, Grains, or Vegetables), then select the specific food from the second dropdown. The GI value, standard serving size, and carbohydrate content will auto-fill from our database. If your food is not listed, switch to Custom Entry mode and enter the GI and carb values manually.
Adjust Serving Size and Carbohydrates
The serving size defaults to the standard amount for that food, but you can change it to match what you actually eat. The carbohydrate content will scale automatically. If you prefer net carbs (total carbs minus fiber), toggle the Net Carbs option to see how that affects your glycemic load calculation.
Review GI, GL, and Blood Sugar Impact
Click Calculate to see the glycemic index value, glycemic load for your serving, and a classification (Low, Medium, or High) for both. The visual donut chart shows where the food sits in the GI zones, and the bar chart shows your GL relative to the low, medium, and high thresholds. For high-GI foods, a healthier swap suggestion will appear.
Build and Track Your Meal
Click Add to Meal to include the current food in your meal tracker. Continue adding foods one at a time to build a complete meal. The meal tracker shows the weighted average GI for the whole meal, total cumulative GL, and a daily GL progress bar to help you stay within your target range throughout the day.
Frequently Asked Questions
What is the difference between glycemic index and glycemic load?
The glycemic index (GI) measures how quickly a food raises blood sugar compared to pure glucose, using a standardized 50-gram carbohydrate portion in a laboratory setting. It tells you the quality of the carbohydrate but not the quantity. Glycemic load (GL) takes both into account by multiplying the GI by the actual grams of carbohydrates in your serving and dividing by 100. This makes GL a far more practical tool for real-world eating. A food can have a high GI but a low GL if you eat a small portion with few carbs. Watermelon is the classic example: GI of 76 (high), but a standard serving has only 6 grams of carbs, giving a GL of just 4.6, which is very low. For managing blood sugar and choosing everyday foods, glycemic load is generally the more useful measure.
How accurate are the GI values in the database?
The GI values in our database are sourced from the International Tables of Glycemic Index and Glycemic Load Values published in Diabetes Care (Atkinson, Foster-Powell, and Brand-Miller, 2008) and updated values from the University of Sydney SUGiRS database, which is the global gold standard for GI testing. GI values are determined through controlled human clinical trials where participants consume the test food and have blood glucose monitored over two hours. However, it is important to understand that GI values are averages — individual responses vary based on personal metabolism, gut microbiome, food preparation method, ripeness level, and what else is eaten at the same time. The values in any database, including ours, represent the best available published evidence but may differ somewhat from your personal glycemic response.
Should I avoid all high-GI foods?
Not necessarily. A food's GI value alone is not a complete picture of its nutritional quality or its impact on your blood sugar in the context of a real meal. Many high-GI foods are also highly nutritious — for example, watermelon (GI 76), pumpkin (GI 75), and parsnips (GI 97) are all high-GI vegetables with excellent vitamin, mineral, and fiber profiles, but they have low to moderate glycemic loads when eaten in typical portions. What matters most is the overall composition of your meal. Combining high-GI foods with protein, healthy fats, and high-fiber vegetables slows digestion and significantly reduces the meal's effective GI. Instead of eliminating high-GI foods, focus on reducing your overall daily glycemic load and making lower-GI swaps where practical.
What is a good daily glycemic load target?
According to guidelines from the Harvard T.H. Chan School of Public Health, a daily glycemic load below 80 is considered a low-glycemic diet and is associated with the best outcomes for blood sugar control, weight management, and reduced chronic disease risk. A daily GL of 80 to 120 is considered medium, and above 120 is high. These targets apply to the total carbohydrate intake over the course of a full day. For practical reference, a typical Western diet often has a daily GL of 120 to 160 or higher. Reducing daily GL can be achieved by choosing whole grains over refined grains, eating more legumes and non-starchy vegetables, limiting sugary beverages and sweets, and controlling portion sizes of high-carbohydrate foods. The meal tracker in this calculator helps you monitor your cumulative GL throughout the day.
How does cooking method affect the glycemic index of foods?
Cooking method can significantly change a food's GI value, sometimes by a large margin. For pasta, cooking al dente (firm to the bite) preserves more of the starch structure and results in a lower GI (around 40-45) compared to overcooked pasta (GI 55-65). Similarly, cooling cooked rice or pasta after cooking causes the starch to retrograde into a more resistant form, lowering GI by 10-15 points. For potatoes, boiling results in lower GI than baking, and leaving the skin on further reduces GI. Ripeness is another key factor for fruits: an unripe banana has a GI of about 42, while a fully ripe banana reaches 58. Adding acid such as vinegar, lemon juice, or sourdough fermentation also substantially lowers GI. These practical cooking strategies can meaningfully reduce the glycemic impact of meals you already enjoy.
Is a low-glycemic diet suitable for people with diabetes?
Research consistently supports low-glycemic diets as a beneficial dietary pattern for people with type 1 and type 2 diabetes, as well as those with prediabetes. Multiple systematic reviews and meta-analyses have demonstrated that low-GI diets reduce HbA1c (long-term blood sugar), fasting glucose, and post-meal blood glucose spikes compared to conventional high-GI diets. The American Diabetes Association acknowledges GI as a useful tool for meal planning. However, the total amount of carbohydrate consumed, medication management, and individual metabolic responses all play important roles. People with diabetes should use this calculator as an educational and planning aid while working with a certified diabetes educator or registered dietitian to develop a personalized meal plan. Do not make significant changes to your diet or medications without consulting your healthcare provider.