Glycemic Load Calculator
GI times carbs over 100, per serving and per meal.
What it does
Glycemic index ranks how fast a carb pushes blood sugar, but portions decide the damage. A high-GI food in a tiny serving can land softer than a medium-GI mountain. Glycemic load multiplies speed by amount.
The tool above takes GI, carbs per serving, and servings, then returns load per serving and for the meal with low, medium, and high bands. It accepts both GI scales and keeps the 10/20 cut points.
The University of Sydney index service publishes tested GI with carbs and precomputed loads, and diabetes associations use the same GL arithmetic with the same bands. Load is why guides counsel portions first and food swaps second.
Use both numbers. Per-serving load compares foods fairly; meal load catches the second helping. When the total runs high, shrink starch, add fiber and protein, or split dessert with the table.
How to use
- Enter the food's GI from a tested table.
- Enter available carbs per serving in grams.
- Enter servings eaten.
- Read GL per serving and the meal total.
- Read both bands: per serving and meal.
- Rebalance portions or pairings from the total.
Formula
- GI
- Glycemic index of the food, 1 to 110.
- carbs
- Available carbs per serving in grams.
- servings
- Servings eaten.
GI runs 0 to 100 (glucose reference); some tables use 1 to 110 with white bread as 100, and this tool accepts both. Carbs means available carbs per serving. Bands: 10 or under low, 11 to 19 medium, 20 and up high.
Worked example
Example: white rice, GL 32.4
One serving of white rice, GI 72 with 45 g carbs.
- White rice: GI 72, 45 g carbs, 1 serving.
- Serving GL: 72 x 45 / 100 = 32.4.
- Meal GL: 32.4 x 1 = 32.4.
- Band: 20 and up is High.
- Pair with protein and veg to blunt the spike.
Reference table
| Food | Serving GL | Band |
|---|---|---|
| Apple, medium | About 6 | Low |
| White rice, 1 cup | About 32 | High |
| Spaghetti, 1 cup | About 24 | High |
| Lentils, 1 cup | About 9 | Low |
| Honey, 1 tbsp | About 10 | Low edge |
Limits
- Estimates response; people, cooking, and mix vary.
- Needs tested GI; guessed GI voids the math.
- Available carbs only; fiber math differs by label.
- Not medical advice; diabetics dose with clinicians.
Common mistakes
- Ranking foods by GI while ignoring portions.
- Using total carbs where net is labeled.
- Guessing GI instead of looking it up.
- Calling seconds free on low-GI foods.
- Chasing single foods instead of meal totals.
Try it yourself
Quick checks. Answers sit tucked under each question.
GL for apple GI 36, 25 g carbs, 2 servings?
Serving GL is 36 x 25 / 100 = 9. Meal is 18, band Medium. Two servings flip Low to Medium.
GL for spaghetti GI 49, 48 g carbs, 1 serving?
Serving GL is 49 x 48 / 100 = 23.5. Meal is 23.5, band High.
Questions
GI vs GL: what is the difference?
GI ranks carb speed from 0 to 100 against glucose; GL multiplies by the actual carbs eaten. Watermelon has high GI but low GL per slice, which is why load beats index for meals.
What counts as low, medium, high?
10 or under low, 11 to 19 medium, 20 and up high, per serving or per meal. The page bands both so a low-GI food eaten triple still flags correctly.
Does low GL guarantee flat blood sugar?
No. Fat, protein, fiber, acidity, and cooking all shift absorption. Use GL to compare portions, then watch your own meter or energy for the verdict.
Where do I find GI and carbs?
The Sydney index database lists tested GI with carbs per serve and precomputed GL. Pack labels give carbs; the database or tables give GI. Multiply and divide by 100.
How do I lower a meal's load?
Boiling less, cooling rice or potatoes (resistant starch), smaller portions, and whole fruit over juice all lower the meal total. Order matters too: veg and protein first.
What is a sensible daily total?
Roughly under 100 a day for low-load eating patterns in common guides, spread across meals. One 32-point serving fits if the rest of the day runs light.