InputTestHub

Social Media Safe Zone Checker

Crops your image to a platform's frame, overlays the bands its interface covers, and measures whether anything is sitting in them.

YouTube & Social Nothing uploaded No sign-up Free, unlimited
YouTube & Social tool
Drop your post image hereany size — it is cropped to the platform frame in your browser, not uploaded
Add a file to begin.
In short A safe zone is the part of a vertical post that no interface element sits on top of, and it is much smaller than people expect: on a Story roughly the top 14% and bottom 20% of the frame belong to the platform, and on Reels and TikTok the bottom third is caption, audio strip and buttons, with a further band down the right-hand side for the follow, like, comment and share column. Two separate things go wrong. The first is the crop — an image that is not already 9:16 is filled to the frame and centred, so the edges are cut before any overlay is considered. The second is placement, and it is only visible once your own image is inside the frame, which is why a table of dimensions cannot answer it. Treat every published percentage as a figure that drifts: platforms move their controls, so the margins here are all editable rather than fixed.

How to use the Social Media Safe Zone Checker

  1. Drop in the image you are about to post.
  2. Pick the platform, or choose Custom and type your own frame and margins.
  3. Read the overlay: red is the platform's, green is yours.
  4. Download the marked-up version to send to whoever made the graphic.

About the Social Media Safe Zone Checker

The Social Media Safe Zone Checker crops your image to a platform's frame, overlays the bands its interface covers, and measures whether anything is sitting in them. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.

What people use it for

  • Checking that a Story headline is not sitting under the caption bar.
  • Seeing how much of a landscape photo survives the crop to 9:16.
  • Producing a marked-up reference image for a designer or a client.

Details

CropCover fit, centred — the image fills the frame and the overflow is cut
OverlayOccluded bands in red, the safe rectangle dashed in green
MeasurementShare of pixels in each band that differ from that band's own background
DownloadsThe marked-up frame, the safe area on its own, and the plain crop
MarginsEvery one is editable, because platforms move their controls
The safe rectangle is drawn from the four margins together, so it is the intersection of every band rather than the largest one — that is the area that survives on every device, including the phones with the tallest notches and the deepest gesture bars.

Where this tool stops

Static images only, and one platform at a time. It models the crop and the interface bands; it does not model a platform's own compression, which is the other thing that changes how a post looks once it is live.

Frequently asked questions

Can it tell whether my text is covered?
It can tell you whether a band is empty or not, which is a different and more honest claim. For each occluded band it counts the share of pixels that differ from that band's own median brightness by a visible margin — flat sky reads as empty, a headline or a logo reads as content. It cannot read the text, so treat a warning as "something is in this band" rather than "your headline is buried".
Where do the percentages come from?
They are the platforms' published guidance for their own ad and creator formats, and they change — a platform that moves its caption bar does not tell anyone. That is exactly why every margin on this page is an editable number rather than a constant baked into the code: if a figure has drifted you can correct it here, instead of being handed a confident wrong answer.
Why is so much of my photo missing?
Because a 9:16 frame is very tall. A landscape 16:9 photo placed into it keeps only the middle third of its width — the "lost to the crop" figure tells you exactly how much. Composing for vertical from the start is the only real fix; there is no crop that recovers what was never in the frame.
What is the difference between this and the Social Media Image Size Guide?
The guide is a reference table of dimensions and it never sees a file. This takes your actual image, crops it the way the platform will, and measures it. They answer different questions: what size should I export, and did this particular image survive.
Is my image uploaded?
No. It is read with FileReader, drawn on a canvas and measured, all inside this tab. The three downloads are produced by your own browser. Nothing is sent and nothing is kept.
Does the Social Media Safe Zone Checker cost anything?
There is no cost and no cap. The Social Media Safe Zone Checker is not a demo of a paid product, so nothing is held back or watermarked.
Can you see what I put into this tool?
No. The Social Media Safe Zone Checker runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
What do people use the Social Media Safe Zone Checker for most?
Typical uses: checking that a Story headline is not sitting under the caption bar. Seeing how much of a landscape photo survives the crop to 9:16. Producing a marked-up reference image for a designer or a client. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Where does the Social Media Safe Zone Checker stop being reliable?
Static images only, and one platform at a time. It models the crop and the interface bands; it does not model a platform's own compression, which is the other thing that changes how a post looks once it is live. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What are the key numbers for the Social Media Safe Zone Checker?
Crop is Cover fit, centred — the image fills the frame and the overflow is cut. Overlay is Occluded bands in red, the safe rectangle dashed in green. Measurement is Share of pixels in each band that differ from that band's own background. These are printed on the page itself, so you do not have to take them on trust.
Is there a file size limit?
There is no limit set by us, because your file is never uploaded — the only ceiling is the memory your own browser will give the tab. Very large files simply take longer to process, and a phone will give up sooner than a desktop.

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