In two studies, the impact of eight front-of-pack nutrition labelling formats that differed in complexity was investigated across four European countries. In total 1630 men and women (18-55 yrs) were recruited from Internet panels in the United Kingdom, Germany, Italy and the Netherlands for study 1 and 776 in Italy and the United Kingdom for study 2. Participants evaluated several products (healthier and less healthy variants of the same product category) with a front-of-pack nutrition labelling format. The first study evaluated different labelling formats on consumer friendliness (comprehension, liking and credibility) and the second study measured the effect of the different labelling formats on decision-making (usage intention and process time). The results indicated minor differences in consumer friendliness and usage intention between simpler (such as Healthier Choice Tick, Smileys and Stars) and more complex front-of-pack nutrition labelling formats (such as Multiple Traffic Light, Wheel of Health and GDA scores). Endorsement by national and international health organisations strongly increased the labelling formats' credibility. Participants needed significantly less time to evaluate simpler front-of-pack labelling compared to the more complex labelling format. Thus simpler front-of-pack labelling formats seem more appropriate in a shopping environment where quick decisions are made.