Threads Safe Zone Checker (Free — Overlay Your Own Image)

Threads enforces a roughly 4:5 maximum aspect ratio for single images in the feed. If you upload something taller — a portrait shot, a 9:16 story-style graphic — Threads center-crops it so only the middle portion shows in the scroll view. The top band and an equal bottom band are trimmed away. A viewer who keeps scrolling never sees those edges; only someone who taps through does.

This cropping is purely a display constraint, not a file change — the full image is still there when someone opens it. But in a fast-scrolling feed, that first impression is what counts. If your key text, product shot, or face sits close to the top or bottom margin of a tall image, there is a real chance it lands in the trimmed zone. This overlay makes that risk visible before you publish.

Two additional elements sit at the lower portion of an in-feed Threads image. When you add alt text, Threads renders a small "ALT" chip in the bottom-right corner of the media itself — useful accessibility signalling, but it does overlap whatever is behind it. Avoid placing fine detail or small text in that bottom-right region if you want it fully readable.

The like, reply, repost, and share icons appear just below the image in the thread layout. On a near-full-bleed image, the bottom-left corner visually runs right into that action row. Nothing is technically covered — those icons live below the frame — but the visual proximity means critical content placed very low and left can feel cluttered or compete with the interaction area. Keeping meaningful elements above the lower fifth of the frame avoids both issues.

The readout under the preview reports one thing: how much of the total frame each zone covers, as a percentage of the full image area. That number is pure rectangle geometry computed from the fractional bounds in our research data. The tool does not look at your image, does not attempt to identify your subject, and does not generate a "content blocked" score — because no browser tool can reliably know what the important part of your image is.

Use the legend toggles to isolate the crop band or the ALT badge while you fine-tune placement, and read each zone note for exactly what it represents. The positions are derived from observed Threads behaviour as of June 2026, but Meta updates its layout between app versions and devices — treat the overlay as an accurate guide and leave yourself a margin rather than placing content flush to a zone edge.