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Free tool

Aspect ratio calculator that knows about placements

Get the missing dimension in a keystroke. Then, if you want it, check one creative against real social placements and see exactly what each one crops away.

Your file stays in this browser. It is not uploaded, stored or sent to analytics.

Why this one

What this tool gets right

The plain calculator comes first

Enter a ratio and one dimension, or two dimensions and get the reduced ratio. No file, no placements, no sign-up, no scrolling past a marketing funnel to reach the answer.

Crop maths you can audit

Every placement shows the exact crop rectangle in source pixels and the percentage trimmed from each edge. The same numbers go into the CSV, so production gets what you saw.

Your file never leaves the tab

Dimensions are read with the browser's own decoder. Nothing is uploaded, nothing is stored, and no filename, dimension or crop coordinate is sent to analytics.

It will not call a crop safe

Safe zones are dated configuration with their method stated. When one is unverified the tool says so rather than drawing a reassuring box, because a wrong safe zone is worse than none.

How it works

Three steps, about thirty seconds

01

Do the ratio maths

Pick a preset or type a custom ratio, give it one dimension, and read the other. Or go the other way and reduce two dimensions to a ratio.

02

Add a source, if you have one

Choose a file to read its dimensions locally, or type them in. Manual entry works exactly as well; the file is only a convenience.

03

Check the placements

Select the surfaces you are shipping to, move the focal point, and read the trims. Copy or download the production spec when it looks right.

Why one creative rarely covers every placement

A 1:1 square and a 9:16 story are not two sizes of the same picture. Going from one to the other throws away nearly half the frame, and cover cropping always takes it from the same place: whichever edges are longest relative to the target. That is what the trim percentages are for. Seeing that a placement loses 44 percent off the sides tells you immediately whether your subject survives it, and whether you need a second composition rather than a crop. The geometry answers that question; no amount of automated cropping can.

Focal points move the problem, they do not solve it

Moving the focal point shifts the crop rectangle within the source and clamps it at the edges, so the subject stays in frame. It cannot create pixels that were never there, and it cannot tell you that the result looks good, because nothing here inspects the image's contents. That is a deliberate limit. There is no subject detection, no face detection and no text detection in this tool, so it never claims a crop worked. It tells you what is kept, what is cut, and where the platform is going to draw its own interface on top.

What this calculator does not do

  • It does not generate, resize, transcode, compress or export a file.
  • It does not detect faces, logos, text or subjects, and never judges whether a crop looks good.
  • It does not upload media or connect to any social platform.
  • It does not validate file size, codec, duration, frame rate, audio, ad policy or content policy.
  • Placement dimensions and safe zones are dated configuration and can go out of date when a platform changes its layout.
  • No profile here is verified against first-party guidance yet, so no crop is described as safe.
  • Video preview frames are not extracted; dimensions and crop maths still work.

Questions, answered

Yes, with no account and no limits. It is arithmetic running in your browser, so there is nothing to meter.
No. The file is read by your own browser to get its dimensions and, for images, to draw the preview. It never touches a server, and it is released from memory when you pick another one or leave the page.
Choose the ratio, say whether you know the width or the height, and enter it. The other one appears immediately, rounded to a whole pixel, with the unrounded value shown when rounding actually changed something.
For each placement you select: the target size and ratio, the exact crop rectangle taken from your source, the percentage trimmed off each edge, and whether the crop is small enough that the file would need upscaling.
The area of the frame that platform interface elements do not cover: captions, action buttons, reply bars, duration badges. Keeping your subject and any text inside it is what stops a logo ending up behind a button.
They are conservative estimates, dated and labelled in the tool, and every profile currently says so. Platforms change their layouts, so treat them as guidance and check the current specification before committing a production file.
No. It gives you the geometry: what to crop, from where, and what you lose. Cropping and exporting happen in whatever tool you already use, and Advibly is where you would generate the creative in the first place.
Yes, for the dimensions and the crop maths. Choose a video file and its width and height are read from the metadata. There is no video preview frame, because extracting one reliably across codecs is not something a browser guarantees.

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