What's the Aspect Ratio Requirement for a Facebook Feed Image Ad?

A Facebook or Instagram Feed image ad must fall within a 4:5 minimum and a 1.91:1 maximum aspect ratio, with Meta recommending a 1:1 (square) ratio as the default that displays most consistently across placements. An image outside that range either gets cropped by Meta's system or rejected during upload, depending on how far it deviates from the accepted range.

The Three Numbers That Matter

Meta's ad specs for Feed placements define three reference points rather than a single fixed ratio: a 4:5 minimum (taller, more vertical images), a 1.91:1 maximum (wider, more landscape-oriented images), and a 1:1 recommendation that sits squarely in the middle. A square 1080x1080px image satisfies the 1:1 recommendation directly, while a portrait-style 1080x1350px image sits at the 4:5 floor.

Why Meta Recommends the Middle, Not Either Extreme

A 1:1 square image avoids the main risk that comes with either edge of the allowed range: an image at the 1.91:1 maximum can get awkwardly cropped on placements designed around a narrower feed column, while one at the 4:5 minimum can leave unwanted empty space on wider placements. The square format is the one ratio that renders predictably whether the ad shows in a narrow mobile feed column or a wider desktop placement, which is why Meta's own guidance defaults to it rather than to either boundary of the accepted range.

Tolerance Isn't Zero, But It's Tight

Ad-spec guides citing Meta's documentation note that Facebook Feed placements allow a small aspect-ratio tolerance — commonly cited around 1-3% — meaning an image doesn't need to hit the exact ratio pixel-for-pixel to be accepted. That tolerance is narrow enough that it should be treated as a margin for rounding error in image export, not as room to deliberately submit an off-ratio image and expect it to pass.

Minimum Resolution Still Applies Separately From Ratio

Aspect ratio and resolution are different constraints that both have to be satisfied. Meta's guidance for Feed image ads commonly cites a 1080x1080px minimum for the 1:1 recommended format, and a minimum width of roughly 600 pixels regardless of which accepted ratio is used — so an image can be the correct ratio and still get rejected or appear soft if it doesn't also meet the minimum pixel dimensions.

How to Prepare Images Within These Rules

• Default to 1:1 (1080x1080px) unless you have a specific reason not to. It's the one format Meta explicitly recommends for consistent rendering across Feed placements.
• If using a non-square ratio, stay inside 4:5 to 1.91:1 — don't treat those as soft guidelines. Images outside that range get cropped or rejected rather than scaled to fit.
• Export at full resolution, not the display size. Meeting the minimum pixel dimensions (not just the ratio) is a separate requirement that low-resolution exports can fail even at the correct aspect ratio.

Bottom Line

Build Facebook and Instagram Feed image ads as 1:1 squares by default, and if you need a different shape, stay inside the 4:5-to-1.91:1 range rather than pushing to either edge of what Meta allows.

Source: Meta Business Help Center, Facebook and Instagram ad image specifications and creative guidance.