Which Video Aspect Ratio Should You Use?

Cropping a video changes its shape by trimming the edges of the frame to a new aspect ratio. Evoke AI center-crops your clip to 16:9, 9:16, 1:1, or 4:3 using FFmpeg inside your browser, so it fits the platform you are posting to. Nothing is uploaded, there is no account or watermark, and no AI API is involved — the video is processed entirely on your device.

Why aspect ratio matters so much now

Every platform has a shape it prefers. YouTube and most players are built for widescreen 16:9, while Reels, TikTok, and Stories are vertical 9:16 and fill a phone screen top to bottom. Square 1:1 performs well in feeds because it takes up more vertical space than widescreen, and 4:3 suits certain classic or presentation contexts. When a video is the wrong shape, the platform pillarboxes it with black bars or crops it unpredictably, which looks unprofessional and can cut off the subject. Cropping to the right ratio yourself means the important part of the frame stays centered and the video fills the space as intended.

How to crop a video online, step by step

• Open the free Crop Video tool
• Drag your video into the box or click to browse
• Choose an aspect ratio: 16:9, 9:16, 1:1, or 4:3
• Run the tool to center-crop the frame to that shape
• Preview the result to confirm the subject stays in frame
• Download the cropped video

Choosing the right ratio for the platform

Pick 16:9 for YouTube, landscape playback, and anywhere a traditional widescreen frame is expected. Choose 9:16 for vertical short-form video like Reels, TikTok, Shorts, and Stories, where filling the phone screen is essential. Square 1:1 is a strong, safe choice for feed posts across most social networks because it looks good on both phones and desktops. Use 4:3 when you want a more classic, boxy frame. The tool crops from the center, so as long as your subject is roughly in the middle of the original footage, it will remain the focus after cropping.

How center-cropping preserves your subject

Center-cropping keeps the middle of each frame and removes the outer edges needed to reach the target shape. Turning a widescreen clip into vertical, for example, trims the left and right sides; turning a tall clip into widescreen trims the top and bottom. Because the center is preserved, a subject framed in the middle stays intact while distracting edges disappear. This is different from squeezing or stretching, which distorts the picture — cropping never warps the image, it simply changes which portion of it you keep, so people and objects keep their natural proportions.

When to crop a video

• Converting a widescreen clip into vertical 9:16 for Reels or TikTok
• Making a square 1:1 version for a feed post
• Removing distracting edges to focus attention on the subject
• Reformatting landscape footage for a portrait story
• Standardizing several clips to one aspect ratio before merging

Cropping does not shrink the picture — it reshapes the frame around what matters.

Why cropping never uploads your clip

The FFmpeg WebAssembly engine loads when you run the crop and processes the video entirely inside your browser tab. Your footage is never uploaded to a server and no AI service is involved, so personal and client work stays private. Because the crop and re-encode use your own processor, a longer or high-resolution clip takes more time than a short one, but nothing leaves your device.

Tips for great crops

• Keep your subject centered when filming so cropping has room to work
• Choose 9:16 for full-screen vertical and 1:1 for versatile feed posts
• Preview before downloading to confirm nothing important is cut off
• Crop before adding a watermark so the logo lands inside the final frame

Frequently asked questions