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Glycaemic Load Calculator

The glycaemic index only says how fast a food raises blood sugar. Watermelon scores high, yet a slice holds little carbohydrate, so its real impact is small. Index times portion — the glycaemic load — is what the body actually meets.

Your numbers

Glycaemic load

21

Calories

120kcal

What it means

A load of 20 or more is high — a smaller portion, or splitting it, works better.

Formula

Glycaemic load = Glycaemic index × Carbs ÷ 100

Under 10 is low, 10–19 moderate, 20 and above high. Across a whole day, around 100 is the usual reference point.

What to enter

InputDefaultAccepted range
Glycaemic indexHow fast a food raises blood sugar, regardless of portion.700 ~ 120
Carbs (g)Grams of carbohydrate for the day; each gram is 4 kcal.300 and up

Step by step

FormulaGlycaemic load = Glycaemic index × Carbs ÷ 100
With the default numbersGlycaemic load = 70 × 30 ÷ 100
AnswerGlycaemic load = 21

Quick reference table

Results when only Glycaemic index changes and everything else stays put.

Glycaemic indexGlycaemic loadCalories (kcal)
3510.5120
52.515.8120
7021120
10531.5120
12036120

What each result means

ResultAt default values
Glycaemic loadIndex times portion — under 10 is low, 20 and up is high.21
Calories (kcal)Energy, in kilocalories.120

Common mistakes

Under 10 is low, 10–19 moderate, 20 and above high. Across a whole day, around 100 is the usual reference point.

Glossary

Glycaemic index
How fast a food raises blood sugar, regardless of portion.
Carbs
Grams of carbohydrate for the day; each gram is 4 kcal.
Glycaemic load
Index times portion — under 10 is low, 20 and up is high.
Calories
Energy, in kilocalories.

Frequently asked questions

Q. How is Glycaemic Load Calculator calculated?

Glycaemic load = Glycaemic index × Carbs ÷ 100 — The glycaemic index only says how fast a food raises blood sugar. Watermelon scores high, yet a slice holds little carbohydrate, so its real impact is small. Index times portion — the glycaemic load — is what the body actually meets.

Q. Can you walk through an example?

With Glycaemic index 70, Carbs 30g, the answer is Glycaemic load 21.

Q. What do I need to enter?

Enter Glycaemic index, Carbs. The result recalculates as you type, and an empty box counts as zero.

Q. How much does the answer move if I change a number?

Changing only Glycaemic index moves the answer to Glycaemic index 35 → Glycaemic load 10.5 and Glycaemic index 120 → Glycaemic load 36. The table below lays out five steps.

Q. How are the numbers rounded?

Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.

Q. Anything to watch out for?

Under 10 is low, 10–19 moderate, 20 and above high. Across a whole day, around 100 is the usual reference point.

Related calculators

These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.