Almost every “why does my post look wrong” problem is one of three things: the file was the wrong shape, the interface covered the part you cared about, or the export happened before the layout was planned. This page is the shared background behind the guides above. The complete specification lives in the Instagram sizes and aspect ratios guide.
What happens to a file on upload
Instagram does not publish its media pipeline, so everything in this section is observed behaviour rather than documentation — but it is consistent enough to design around. Two things happen to a file you upload.
First, it is re-encoded. Your carefully exported JPEG or PNG is decoded and compressed again on Instagram’s side, and you have no control over the settings. This is why flat colour gradients band, why fine text on a busy background goes mushy, and why exporting at maximum quality helps only up to a point: you are handing better input to a compressor whose output you do not choose.
Second, it may be resized. Uploads wider than 1080 pixels are commonly observed being downscaled to roughly that width. Exporting a 4,000-pixel-wide image does not buy sharpness; it buys a downscale you did not tune. Exporting at exactly the target dimensions gives the compressor the least work to do.
| Placement | Ratio | Pixels to export |
|---|---|---|
| Feed portrait — the most screen space | 4:5 | 1080 × 1350 |
| Feed square | 1:1 | 1080 × 1080 |
| Feed landscape — the widest the feed allows | 1.91:1 | 1080 × 566 |
| Reels and Stories | 9:16 | 1080 × 1920 |
The feed accepts anything between 1.91:1 and 4:5. Inside that window nothing is forced; outside it, something gets trimmed. A file taller than 4:5 loses the top and bottom, a file wider than 1.91:1 loses the sides, and a centre crop takes roughly half the loss from each edge. The complete size and ratio spec covers every placement, and the image and video size checker will tell you how many pixels a given file loses and re-cut it around a focal point you choose rather than the centre.
The interface is part of your canvas
This is the point most people learn the expensive way. On Reels, the top strip, the caption and audio row along the bottom, the action rail down the right side and the profile row at the lower left all sit on top of your video. In Stories, the progress bars and header cover the top and the reply bar covers the bottom — and the left and right thirds of the screen are tap targets that skip backwards and forwards, so anything interactive placed there is unreachable. In the feed, the 1:1 grid thumbnail crops a 4:5 post top and bottom, which is why text pinned to the bottom edge of a beautiful post is missing from your profile grid.
None of these insets are published by Instagram. The ones drawn by the safe zone checker are measured off the current app and rounded, and they shift with device shape — a tall phone with a notch loses more at the top than an older 16:9 handset. Treat them as generous margins, not exact boundaries. The guide to Reels and Stories safe zones goes through each one.
Carousels and grids have to be planned before export
Both are multi-file formats where the composition lives across the files, which means the decision that matters happens in your editor, not in the Instagram app.
A seamless carousel — one wide image cut into panels that continue across the swipe — only works if every panel is exported at the same height and in the correct order, and if nothing important sits within about 6% of any panel edge, because that is where the seam and the interface chrome land. The slide counter chip sits in the top-right corner of the first panel, and the first panel is also the one that gets the 1:1 grid crop. The carousel splitter cuts a single wide image into 4:5, 1:1 or 3:4 panels and draws those guides over the preview without burning them into the export. How to make a seamless carousel covers the source-image maths.
A grid layout — a checkerboard, a row pattern, a panorama split across three tiles — has the same property one level up: it only reads if you can see the arrangement before you commit to a posting order, and the order is not editable afterwards. The grid planner holds up to eighteen images in a real three-column layout so you can reorder and export the plan first.
What captions and hashtags actually do now
Three hard numbers, and they are stable: a caption is limited to 2,200 characters, the feed collapses it to a “… more” link after roughly 125 characters, and Instagram accepts 30 hashtags per post and quietly ignores anything past that. The caption length counter tracks all three live against a feed preview.
What those numbers imply for craft is simpler than the folklore suggests. The first 125 characters are the caption most people read, so anything that must land — the hook, the question, the call to action — goes before the cut. Duplicate hashtags between the caption and a comment block do not count twice; they just burn a slot. And the persistent claims about hashtag counts and banned-tag lists are unverifiable: Instagram publishes no such list, and the circulating ones go stale within weeks. The captions, bios and hashtags guide sets out what can actually be said with confidence.