Scribeify

Resize Video Online — Change Dimensions & Ratio

Change width, height, and aspect ratio in your browser. Preset outputs for TikTok (9:16), Instagram (1:1), YouTube (16:9), and custom sizes.

How to use Resize Video Online — Change Dimensions & Ratio in 3 steps

  1. 1

    Upload your video

    Drop a file or browse to select. MP4, MOV, AVI, MKV, WebM supported up to 2 GB.

  2. 2

    Pick a preset or custom size

    Choose 9:16 vertical, 1:1 square, 16:9 landscape, or enter exact width × height in pixels.

  3. 3

    Download the resized video

    Processing runs in your browser via FFmpeg.wasm. Preview before exporting.

Why choose Resize Video Online — Change Dimensions & Ratio

  • Preset social sizes

    9:16 (TikTok/Reels/Shorts), 1:1 (Instagram feed), 16:9 (YouTube/Twitter), 4:5 (Instagram portrait).

  • Crop or fit

    Choose cover (crops to fill) or contain (adds letterbox bars) to handle aspect-ratio changes.

  • Private processing

    Runs entirely in your browser. Your file never leaves your device.

  • Custom background

    Letterbox color options (black, white, blur) when adding bars for fit mode.

  • Free forever

    Unlimited resizing, no watermark, no sign-up.

Who uses Resize Video Online — Change Dimensions & Ratio

  • TikTok and Reels vertical

    Turn a horizontal YouTube clip into a 9:16 vertical for short-form platforms.

  • Instagram square feed

    Center-crop or letterbox to a 1:1 square for clean feed posts.

  • YouTube 16:9

    Resize phone recordings to the standard 1920×1080 YouTube aspect ratio.

Trusted by creators worldwide

4.8 / 5 based on 1,200+ users

Frequently asked questions

What output dimensions are supported?
Presets for 9:16, 1:1, 16:9, 4:5. Custom width and height in pixels up to 4096×4096.
Will resizing reduce quality?
Downscaling is generally lossless at the visual level. Upscaling cannot add detail but produces a usable, larger file.
What is the difference between cover and contain?
Cover crops the video to fill the target size without distortion. Contain adds letterbox/pillarbox bars to preserve the full frame.
Does the output keep the audio?
Yes. Audio is preserved by default. An option to strip audio is available.
Are my files uploaded?
No. All processing runs in your browser.
What output formats are supported?
MP4 with H.264 is the default output. WebM is available as an alternative.

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