What is Aspect ratio?
A plain-English definition, and the tools that work with it.
Aspect ratio is the proportional relationship between an image or video's width and height, written like 16:9 or 1:1. It defines the shape of the frame, and matching the required ratio is what stops a platform from awkwardly cropping or stretching your content.
- Common ratios: 1:1 (square posts), 4:5 (portrait posts), 9:16 (stories/reels), 16:9 (video and thumbnails).
- Cropping to the right ratio yourself keeps control of the framing instead of letting a platform chop the edges.
- Resizing changes the pixel dimensions. Cropping changes the ratio. You often do both to hit a spec.
Tools for Aspect ratio
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Crop Image
Cut an image down to the exact part you want. Drag a crop box, snap to a ratio like 1:1 or 16:9, and export the trimmed area: free, private, in your browser.
Image Resizer
Resize any image to exact pixel dimensions with an optional aspect-ratio lock and ready-made social presets, free and fully in your browser.
Video Cropper
Crop video online in your browser, drag a box over a live preview or pick an aspect preset (1:1, 9:16, 4:5, 16:9) to reframe the picture, then download the cropped clip. No uploads, no account, no watermark.
Video Resizer
Resize video resolution in your browser with FFmpeg: scale MP4, MOV, WebM and MKV to 1080p, 720p, 480p or a custom width and height, lock the aspect ratio or fit-and-pad, then download. Nothing is uploaded.
Aspect ratio problems we solve
Hit one of these? Here's the fix.
- What size should my image be for Instagram?Uploading the wrong ratio means Instagram crops your subject or squashes it. Match the pixels below and it stays sharp and framed.
- I need to make a YouTube thumbnailGet the exact size right so your thumbnail looks sharp on every device and doesn't get rejected for being too big.
- I need a passport-size photoRequirements vary by country and document, so confirm the exact dimensions first, then crop, resize and clean the background to match.
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