How Many Calories in a Mars Bar

There are 228 calories in a standard size Mars Bar, 151 calories in a Snacksize bar, 80 calories in a Funsize and 355 calories in a Duo pack. 

The nutritional profiles of all sizes of Mars bar are very similar, so here's the breakdown across all sizes plus calories in individual sizes, including multipack bars.

Calorie and Nutrition Info for a standard (51g) Mars Bar

| Source: WLR Food Database

Percentage of Calories from Each Macronutrient


Syns in Different Mars Bar Sizes

Using the calories divided by 20 formula gives 11.5 syns for a standard Mars Bar, 7.5 for a Snacksize and 4 for a Funsize.*

Traffic Light Info for Mars Bars


Calories in Different Mars Bar Sizes

Funsize Mars (18g) 80
Snacksize Mars (33.8g) 151
Multipack Mars (39.4g) 177
Standard Bar (51g) 228
Mars Duo Pack (78.8g) 355
1 Bar of Duo Pack (39.4g) 177

Find the Calories in all the Foods You Eat

The calorie and nutrition data provided here are from the Weight Loss Resources verified UK food database.

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Mars Bar Nutrition Info per 100g

Tracking Calories

Research shows that people who keep a food diary are more successful at losing weight - but not everyone wants to use an online diary, for some of us it's just easier to scribble stuff down. Take a look at WLR's easy to use paper food diary

* Syns are a measurement created by Slimming World. The syn values given here are calculated from our research of various sources and a popular formula (calories divided by 20) that works for most products. 

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