Glycemic Load Calculator (GL of any food or meal)
The glycemic load (GL) was developed in 1997 at Harvard by Walter Willett to fix the main limitation of the glycemic index: GI measures speed but ignores quantity. GL multiplies the GI by the actual grams of carbohydrate in your portion: GL = (GI × carbs in grams) / 100. Watermelon has a high GI (76), but a 120 g serving holds only 6 g of carbs, giving GL = 4.5 (low). This calculator asks for the food's GI, the carbs per 100 g (from the label), and your portion size in grams, then returns the GL with its official Harvard classification: low (1–10), medium (11–19), high (20+).
Glycemic load (GL) = Glycemic Index × grams of carbs in the serving ÷ 100. A GL under 10 is low, 11–19 is medium, and 20 or more is high. Example: 150 g of white rice (GI 73, 42 g carbs) = 73 × 42 ÷ 100 = 30.7, a high glycemic load. Aim for a daily total under 100.
When to use this calculator
- You're diabetic and want to control the real blood sugar impact of each plate.
- You read nutrition labels and want to translate 'grams of carbs' into actual glucose impact.
- You're a nutritionist or dietitian building meal plans with daily GL targets.
- You want to compare two recipes with similar carbs but different glycemic index.
- You plan to eat fruit and want to know which raises blood sugar the least.
Worked example: 150 g plate of white rice
- White rice GI = 73.
- Carbs per 100 g = 28 g.
- Portion size = 150 g.
- Actual carbs in the serving = 150 × 28 ÷ 100 = 42 g.
- GL = 73 × 42 ÷ 100 = 30.7 → high.
How it works
2 min readHow to calculate glycemic load
Glycemic load (GL) combines the glycemic index (GI) with the actual amount of carbohydrate in a serving. It was created at Harvard by Walter Willett in 1997 to make the GI useful for real meals — because eating 10 g of a high-GI food is very different from eating 100 g of it.
Glycemic load formula
GL = (GI × carbs in grams) / 100Where carbs in grams = portion (g) × carbs per 100 g ÷ 100. Two steps, one number.
Glycemic load classification (Harvard)
| Glycemic load (per serving) | Level |
|---|---|
| 1 – 10 | Low ✅ |
| 11 – 19 | Medium |
| 20 or more | High ⚠️ |
Daily target: keep the sum of all meals under 100 points.
Glycemic load of common foods (per typical serving)
| Food | Serving | GI | Carbs (g) | Glycemic load |
|---|---|---|---|---|
| Watermelon | 120 g | 76 | 6 | 4.5 (low) |
| Strawberries | 150 g | 40 | 11 | 4.4 (low) |
| Dark chocolate 70% | 25 g | 40 | 11 | 4.4 (low) |
| Apple | 150 g | 36 | 18 | 6.5 (low) |
| Carrots (cooked) | 80 g | 39 | 6 | 2.3 (low) |
| Cooked lentils | 150 g | 32 | 30 | 9.6 (low) |
| Oatmeal (cooked) | 250 g | 55 | 27 | 14.9 (medium) |
| White bread | 30 g | 75 | 15 | 11.3 (medium) |
| Banana | 120 g | 51 | 27 | 13.8 (medium) |
| Sweet potato | 150 g | 63 | 28 | 17.6 (medium) |
| Pasta (white) | 180 g | 49 | 48 | 23.5 (high) |
| Baked potato | 150 g | 85 | 30 | 25.5 (high) |
| White rice | 150 g | 73 | 42 | 30.7 (high) |
| Cornflakes | 30 g | 81 | 26 | 21.1 (high) |
Why a high GI can still mean a low GL
Watermelon is the classic case: GI 76 (high) but only 6 g of carbs per serving → GL 4.5 (low). The amount you eat matters as much as the speed. That's the whole point of GL.
Recommended daily glycemic load
How to lower a meal's glycemic load
Use this calculator alongside USDA tables for accuracy, and consult a dietitian for a personalized plan.
Frequently asked questions
How do I calculate glycemic load?
Multiply the food's glycemic index by the grams of carbohydrate in your serving, then divide by 100: GL = GI × carbs(g) ÷ 100. To get the carbs in your serving, multiply the portion in grams by the carbs per 100 g and divide by 100. Example: 150 g of white rice with 28 g carbs per 100 g = 42 g carbs; GL = 73 × 42 ÷ 100 = 30.7.
What is a low, medium and high glycemic load?
A glycemic load of 1–10 per serving is low, 11–19 is medium, and 20 or more is high. Over a full day, under 100 is considered low and over 120 high.
What's the difference between glycemic index and glycemic load?
GI measures how quickly a food raises blood sugar (speed). GL measures the actual blood sugar impact of a real serving by combining GI with how many carbs you eat (speed × quantity). GL is more practical for meal planning, which is why watermelon — high GI but few carbs per serving — has a low GL.
Where do I find the carb grams and GI for a food?
Take total carbohydrate per 100 g from the nutrition label or the USDA FoodData Central database, and look up the glycemic index on the official Glycemic Index Foundation (University of Sydney) database or Harvard's GI tables.
Does fiber count toward glycemic load?
The original Harvard formula uses total carbohydrates. Some people use 'net carbs' (total minus fiber) for high-fiber foods, since fiber isn't absorbed and blunts the glucose response. Both approaches are common; net carbs gives a slightly lower GL.
Does pasta have a high glycemic load?
It depends on the portion. A 180 g cooked serving has GL ≈ 23 (high), but an 80 g serving is GL ≈ 10 (low). White and whole-wheat pasta have similar GI; the portion is what drives the load.
What's the glycemic load of common fruits?
Most whole fruits are low GL per serving: apple ≈ 6.5, orange ≈ 5, strawberries ≈ 4, banana ≈ 14 (the ripest are higher). The fiber in whole fruit lowers GL compared with fruit juice.
Can glycemic load help me lose weight?
Lower-GL meals tend to keep blood sugar stable, reduce insulin spikes and curb hunger rebounds, which can support weight management. It's one tool among many — total calories still matter.
How do I lower the glycemic load of a meal?
Eat a smaller portion of the carb, add fiber, protein or healthy fat to slow absorption, swap white rice or bread for quinoa, lentils or whole grains, and cook-then-cool starches to build resistant starch.
What daily glycemic load should a diabetic aim for?
Most guidance suggests keeping the total under 100–120 points per day for type 2 diabetes, spread across meals so no single plate spikes glucose. Always confirm your personal target with your doctor or dietitian.