Resize a video for any platform in your browser

Choose a video, pick a shape and a fit, and download the result. Your file never leaves your device.

Free, no sign upNo watermarkNothing is uploadedMP4, MOV and WEBM

Shape

Fit

Size

How it works

  1. Step 1

    Choose a video

    Drop it on the tool or pick a file, up to 250 MB and 10 minutes.

  2. Step 2

    Pick a shape and a fit

    The preview shows exactly what crop, blur fill or bars will do before anything runs.

  3. Step 3

    Resize and download

    The video is processed on your device and saved as an MP4 that plays everywhere.

Which shape for which platform

Instagram accepts reels at any ratio from 1.91:1 to 9:16. YouTube treats uploads that are square or vertical and up to three minutes long as Shorts, and says 16:9 is the standard on a computer.

ShapeSize at 1080Use it for
9:161080 by 1920Reels, Shorts, TikTok and Stories, full screen on a phone
4:51080 by 1350Instagram, Facebook and LinkedIn feed posts
1:11080 by 1080Square placements and feeds that crop to a square
16:91920 by 1080YouTube and anything watched on a computer or TV

Crop, blur fill or bars: what each one costs

Changing a video’s shape always gives something up. Starting from a 1920 by 1080 landscape video:

TargetCrop keepsBars leave picture in
9:1632% of the width32% of the frame height
4:545% of the width45% of the frame height
1:156% of the width56% of the frame height
  • Crop fills the frame and cuts the edges. Best for one person in the middle of the shot.
  • Blur fill keeps the whole picture and fills the empty space with a blurred copy of the video. Best for wide shots on vertical platforms.
  • Bars keep the whole picture with black bars. Best for slides and screen recordings, but not for YouTube, whose help pages ask creators not to add bars because the player adapts to the video’s own shape.

Private by design

The resizer runs FFmpeg compiled to WebAssembly inside your browser. The converter is downloaded once from a pinned version and checked against a fingerprint before it runs; your video is read into memory on your device and the result is saved from there. Nothing is sent to Percify or anyone else, which is also why there is no queue, no account and no watermark.

Long or 1080p videos take longer in a browser than on a desktop app. For videos over 10 minutes, the same job runs with the free FFmpeg command shown below.

Platform facts checked on 16 September 2026 against each platform's own help pages.

Use it from an AI assistant or a script

Every setting is a URL parameter, so an assistant can send a link with the options already chosen. The tool still runs on the person's own device.

ParameterValuesDefaultMeaning
ratio9:16, 4:5, 1:1, 16:99:16Output shape.
fitcrop, blur, padblurcrop fills and cuts edges; blur fills gaps with a blurred copy; pad adds black bars.
quality720, 1080720Short side in pixels. 720 is faster in the browser.

Landscape to Reels, Shorts or TikTok with a blurred background

https://percify.io/tool/resize-video?ratio=9:16&fit=blurffmpeg -i input.mp4 -filter_complex "[0:v]split=2[a][b];[a]scale=720:1280:force_original_aspect_ratio=increase,crop=720:1280,boxblur=20[bg];[b]scale=720:1280:force_original_aspect_ratio=decrease[fg];[bg][fg]overlay=(W-w)/2:(H-h)/2,setsar=1[v]" -map "[v]" -map "0:a?" -c:v libx264 -preset ultrafast -crf 23 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart output_9x16.mp4

Vertical video to a 4:5 feed post, cropped

https://percify.io/tool/resize-video?ratio=4:5&fit=cropffmpeg -i input.mp4 -vf "scale=720:900:force_original_aspect_ratio=increase,crop=720:900,setsar=1" -c:v libx264 -preset ultrafast -crf 23 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart output_4x5.mp4

Any video to a square with bars, in 1080p

https://percify.io/tool/resize-video?ratio=1:1&fit=pad&quality=1080ffmpeg -i input.mp4 -vf "scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2:black,setsar=1" -c:v libx264 -preset ultrafast -crf 23 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart output_1x1.mp4

Every free tool and its parameters, as JSON: percify.io/tools.json

More free tools

Aspect ratio calculator

Pick a ratio and type one side to get the other, or type a width and height to get the ratio. Answers update as you type.

Video to GIF converter

Choose a clip, pick the length, width and frame rate, and download a looping GIF. The file never leaves your device.

Video looper

Choose a video, pick how many times it should play, and download one file. Nothing is re encoded, so it is fast and looks the same.

Need a video that starts in the right shape?

Make a talking video from one photo and your voice, in 9:16 or 16:9 from the start. 2 credits a second, free to try.

Make a talking video

Cancel anytime, no contracts

Frequently asked questions

Everything you need to know before you start.

Choose the video, pick the 9:16 shape, choose crop for a single person in the middle or blur fill for a wide shot, and download. The result is a 720 by 1280 or 1080 by 1920 MP4.

Yes. It runs in your browser, adds no watermark, and needs no account. There is nothing on our side to pay for, because your video is never uploaded.

No. The video is processed on your device with FFmpeg running in WebAssembly and saved from there. Only the converter itself is downloaded, once, and it is checked against a fingerprint before it runs.

Crop fills the new shape and cuts the edges. Blur fill keeps the whole picture and fills the gaps with a blurred copy of the video. Bars keep the whole picture and add black bars. From a 16:9 video, a 9:16 crop keeps about 32% of the width.

Up to 250 MB and 10 minutes in the browser. Larger files are better handled by the free FFmpeg command shown on this page.

Yes. Every option is a URL parameter, for example /tool/resize-video?ratio=9:16&fit=blur, so an assistant can send you a link with the settings already chosen, and /tools.json describes every tool and its parameters.