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Mars Bar Weights and Calories (for All Sizes)

I’ve put this article together (using charts and images) to help you find out everything you need to know about Mars Bar weights and calories.

Including information for all sized bars as sold and per portion size so you can find the most accurate information.

Weight and Calories of a Regular Mars Bar

A regular Mars Bar is a standard-sized bar that is sold individually and the size you’d expect to see in a sweet rack in a local shop.

The ‘as sold’ weight of a regular Mars Bar is 51g (1.8oz) and this sized bar contains 228 calories in total.

This weight might fluctuate slightly, for example, I weighed one on calibrated scales and it weighed 53g.

Regular mars bar on scales

Weight and Calories of half a Regular Mars Bar

If you prefer to cut your Mars Bar in half, then here’s the weight and calorie information for per half a bar serving size:

Half of a regular-sized Mars Bar weighs 25.5g (0.9oz) and contains 114 calories (kcal) in total.

Weight and Calories of a Mars Bar Duo

The Mars Bar Duo is the new version of what used to be known as a king-size Mars Bar before the days of portion control.

So to get around the high calorie/high sugar content, they now class the larger bars as two servings (because nobody ever eats both right?).

The total ‘sold as’ weight of a Mars Bar Duo is 78.8g which contains two servings of 39.4g bars. One 39.4g Duo bar contains 177 calories (kcal) and both bars contain 354 calories (kcal).

I weighed a Mars Bar Duo as one and individually (on calibrated scales) and again the weight was a couple of grams over the sold weight.

Duo mars bar on scales

Weight and Calories of Fun Size Mars Bars

A fun-size Mars Bar is the smallest available bar that you can buy and are sold in multipacks of 13 bars.

Each fun-size Mars Bar weighs 18g (0.6oz) and contains 80 calories (in kcal), making it the lower calorie option when compared to other bar sizes.

Weight and Calories of Snack Size Mars Bars

The snack-sized Mars Bar is a newer bar size and is sold in multipacks of 10 and is a little larger than a fun-size Mars Bar.

The ‘as sold’ weight of an individual snack-sized Mars Bar is 21g (0.7oz) and each bar contains 95 calories (kcal), making it a lighter option when compared to standard or multipack size bars.

Snack size bars bar on scales

Weight and Calories of a Multipack Mars Bar

A Mars Bar sold as part of a multipack might look like a similar-sized bar to a standard Mars Bar, but it’s actually smaller in size and lower in calories.

An individual multipack Mars Bar weighs 39.4g (1.4oz) which is the same size as one-half of a Mars Bar Duo pack. An individual multipack bar contains 177 calories (in kcal) making it 111kcal less than a standard bar.

Weight and Calories of a Mars Bar Ice Cream

A Mars Bar Ice Cream is sold in two sizes, a multipack size of 51ml per ice cream which contains 140 calories (in kcal) and a 74ml individual bar which contains 204 calories per ice cream.

Mars Bar Weight Conversion and Calorie Chart

The chart below shows all of the various Mars weights and calories in one place for quick reference:

Mars Bar typeWeight in
grams & ounces
Calories per bar
in kcal
Half a standard/
regular bar
Whole Mars Bar Duo78.8g/2.8oz354
One Mars Bar Duo bar
(half a pack)
Fun-size Mars Bar18g/0.6oz80
Snack-size Mars Bar21g/0.7oz95
Multipack Mars Bar39.4g/1.4oz177
Individual Mars Bar
Ice Cream
74ml/2.5 fl oz140
Multipack Mars Bar
Ice Cream
51ml/1.7 fl oz204

Equipment and Information Used for This Article

I used precision scales that weigh to 0.01 of a gram which is regularly calibrated with a 100g weight. For more information see my recommended weighing scales here.

To make sure the information in this article is accurate, I researched and cross-referenced various sources (as well as original research) to obtain the correct weights and calories.

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