How Many Calories are in a Block of Hartley's Jelly?

December 31, 2025 •

3 min read

A standard 135g Hartley's jelly block contains approximately 396-399 calories in its dry, concentrated form, while a sugar-free block contains significantly fewer, about 36 calories when prepared. The calorie count for a block of Hartley's jelly depends heavily on the type and preparation.

Quick Summary

The calorie content of a Hartley's jelly block varies by type. A standard block contains around 399 kcal (dry), yielding approximately 396 kcal once prepared. The sugar-free version is much lower in calories.

Key Points

Standard Block Calories: A dry 135g standard Hartley's jelly block contains approximately 399.6 kcal, which distributes to about 396 kcal once prepared into a full pint.
Prepared vs. Unprepared: Calorie counts on packaging usually refer to the prepared jelly per serving (e.g., 99 kcal per 150g serving for standard).
Sugar-Free Block Calories: A prepared sugar-free block, made from a 23g sachet, contains only around 36 kcal in total, with 9 kcal per 145g serving.
10 Cal Pots: Ready-to-eat 10 Cal pots contain fewer than 10 calories each and are a convenient low-calorie option.
Calorie Source: The main calorie source in standard jelly is sugar, while sugar-free versions use artificial sweeteners.
Add-ins: Any additional items like fruit or cream will increase the total calorie count of your dessert.
Product Type Matters: The exact calorie count depends entirely on whether you're using a standard block, a sugar-free block, or a ready-to-eat pot.

Standard Hartley's Jelly Block Calories

For the most common type of Hartley's jelly—the standard 135g block—the calorie information can be somewhat confusing. It's crucial to distinguish between the calorie count of the dry, concentrated cubes and the final, prepared product after adding water.

Unprepared (dry block): The 135g dry block contains the full amount of calories from its ingredients, mainly sugar and glucose-fructose syrup. A 135g block, based on per-100g data, contains approximately 399.6 calories (296 kcal per 100g multiplied by 1.35). Another source lists it at 296 kcal per 100g, also confirming roughly 399 calories for the block as sold.
Prepared (liquid jelly): When the block is prepared with water to make 1 pint (570ml), the total calorie content is distributed across the entire volume. A standard 135g block is typically divided into 4-6 servings. As an example, a 150g serving of prepared standard jelly is listed at 99 kcal. If the block makes 4 servings of 150g, the total is 396 kcal, which is consistent with the dry block's value.

Sugar-Free Hartley's Jelly Block Calories

For those watching their calorie intake, the sugar-free variety offers a low-calorie alternative.

Unprepared (dry sachet): Hartley's sugar-free jelly is often sold as a twin pack of 23g sachets. The calories in the dry powder are minimal, coming from the gelatin and other flavourings.
Prepared (liquid jelly): Once prepared with water, the calories are negligible. A typical 145g serving contains just 9 kcal. Since a sachet makes 4 servings, the entire block of prepared jelly contains only 36 calories (9 kcal x 4). This makes it an ideal low-calorie treat.

Comparison of Standard vs. Sugar-Free Jelly

Choosing between the two depends on your dietary needs and preferences. Here is a clear comparison based on a prepared, four-serving block of jelly.


Feature	Standard Jelly (135g block)	Sugar-Free Jelly (23g sachet)
Total Calories (prepared)	~396 kcal	~36 kcal
Calories per serving (145-150g)	~99 kcal	~9 kcal
Main Calorie Source	Sugar and glucose syrup	Negligible, artificial sweeteners
Sugar Content	High	Sugar-free
Suitability	Classic dessert option	Diet-friendly, lower-calorie

Ready-to-Eat Pots

In addition to the blocks, Hartley's also offers ready-to-eat jelly pots. These come in standard and 10 Cal versions. The latter is explicitly marketed for its low-calorie content.

10 Cal Jelly Pots: As the name suggests, these pots are guaranteed to contain 10 Calories or fewer per pot, making them a very convenient low-calorie dessert option. Some flavours may have as few as 7 kcal per pot.
Standard Jelly Pots: These will contain more calories than their 10 Cal counterparts, with typical values varying by flavour. For instance, a 125g standard strawberry pot has about 36 kcal.

Important Considerations for Calorie Counters

Portion Size is Key: The most common mistake is to misinterpret the calorie information on the packaging. The values for "per serving" and "per 100g" refer to the prepared product, not the dry block. Always consider how many servings the jelly block will be divided into.
Add-ins Affect Calories: Any fruit, cream, or other ingredients added to the jelly will increase the total calorie count. If you are tracking your intake, remember to factor these in. For a healthier option, pairing sugar-free jelly with fresh, low-calorie fruits is an excellent choice.
Ingredient Variations: Some of the standard jellies use pork gelatine, while some sugar-free versions use vegetarian alternatives. It's worth noting these differences, though they do not significantly impact the calorie count.

Conclusion

To determine the total calories in a block of Hartley's jelly, it is essential to identify the specific product. A standard 135g block will contain roughly 396-399 calories when prepared, divided among its servings. In contrast, the sugar-free sachet blocks offer a significantly lower-calorie option, with a prepared block containing around 36 calories. For convenience, the 10 Cal ready-to-eat pots provide a pre-portioned treat of fewer than 10 calories. Regardless of your choice, understanding the difference between the dry and prepared product is key to accurate calorie tracking.

Learn more about Hartley's products on their official website.

Frequently Asked Questions

The calories listed on the packaging for Hartley's jelly blocks, particularly for serving sizes, refer to the prepared product after water has been added. The dry block contains more concentrated calories.

A standard 135g block, when prepared, contains approximately 396 calories in total. This is distributed over four servings, with each serving of about 150g containing 99 calories.

A sugar-free Hartley's jelly block, made from a 23g sachet, contains only about 36 calories in total when prepared. This works out to just 9 calories per 145g serving.

No, Hartley's makes ready-to-eat jelly pots in addition to blocks. Their '10 Cal' pots contain 10 calories or fewer per pot and are a different product from the blocks that require preparation.

For both standard and sugar-free varieties, the calorie count is generally consistent across different flavours, as the base ingredients are the primary source of calories. Any variation is usually minor.

Yes, Hartley's sugar-free jelly is an excellent choice for a low-calorie diet. It contains fewer than 10 calories per serving and is free from added sugars, making it a guilt-free dessert option.

The calories in standard Hartley's jelly come almost entirely from sugar and glucose-fructose syrup, which are the main ingredients providing sweetness and energy.