Instagram post size
Check a photo against the resolution range in Instagram’s Help article. 1080 × 1350 is inside that range. It is not the only size, and it is not the portrait edge.
Check a photo
The result stays on this device.
What the article says
The article says Instagram uploads a photo at the best quality it can, up to a width of 1080 pixels. A photo whose width is between 320 and 1080 keeps its original resolution when its aspect ratio is between 1.91:1 and 3:4. The article’s own example of that ratio, at a width of 1080, is a height between 566 and 1440. 1080 ÷ 1.91 is about 565.4, and the article writes 566. 1080 × 4 ÷ 3 = 1440, so 3:4 is the portrait edge.
A ratio outside that span is cropped to a supported ratio. A width above 1080 is sized down to 1080. A width below 320 is enlarged to 320. This page reports those sentences separately. It does not invent the pixel size after a resize.
1080 × 1350
1080 × 1350 is 4:5. That height sits inside 566 to 1440. Some size guides stop the portrait edge at 4:5. This article’s portrait edge is 3:4, which is 1080 × 1440. Meeting 4:5 does not make that file the required post size.
What this article does not cover
The article is about photos you share. It does not publish a story size, a reel size, a profile photo, a highlight cover, a profile-grid crop, or a file-size limit. 1080 × 1920 is not a size in this article. This page does not check a publishing API, and it does not resize the file.
Source, indexed 2026-10-16: Image resolution of photos you share on Instagram. For a Discord banner, use the Discord banner size page.