Instagram Chief, Adam Mosseri recently explained why carousel posts get more reach than single photo posts. According to Mosseri, there are two main reasons for this trend.

Multiple media formats

Mosseri said having multiple images or videos in a single post encourages users to engage more with the carousel. “Multiple pieces of media are going to mean more interactions with your carousel posts.” 

When users scroll through a carousel, it presents them with several media options. This increases the post's visibility, Mosseri explained. “More interactions is going to mean more reach on average.” 

Algorithmic advantage

Mosseri said that, when users see carousel posts but don't swipe, Instagram often gives them a second chance by auto-swiping to the next piece of media. 

Music on carousels 

Mosseri also talked about a new opportunity for carousels: “Using music on carousels and photos now makes them eligible to be shown in the Reels tab. He claimed that this can also boost engagement and “help with reach.”