Instagram 3:4 size: 1080×1440 for the new grid

Both work in 2026. The difference is what happens on your profile. The grid crops every post to 3:4, which is narrower than 4:5, so a 4:5 photo loses a sliver from each side while a 3:4 photo is shown whole. In the feed the two look almost identical, with 3:4 a touch taller.

Choose 3:4 when the composition runs edge to edge (portraits with hair at the top of the frame, full-body shots, text near the edges). Choose 4:5 when you already have a library edited at that ratio and don't want to recrop; the loss in the grid is small.

If you shoot on a phone, 3:4 is the native sensor ratio, so exporting at 1080×1440 keeps the full frame with no cropping at all.

1. It crops to exactly 3:4 around the position you choose by dragging the preview.
2. It resizes to 1080×1440 in steps, so fine texture survives the downscale.
3. It applies a light sharpen on the final pixels.
4. It finds the JPEG quality that lands between 500 KB and 1 MB.