Resize Video: Online Video Resizer & Aspect Ratio Changer

Change video aspect ratio or resolution for TikTok, Reels, Shorts, Instagram, and YouTube.

10M+ files processed since 2021

Maybe looking for:Crop video· Crop video Video compressor· Video compressor Convert video· Convert video

See the difference

Play Original 16:9, then Resized 9:16.

Made with Resize video, 9:16 with blurred background

How to resize a video

1
Add your video and pick where it will be posted: TikTok, Reels, Shorts, Square (1:1), Instagram (4:5), or YouTube (16:9).
2
Press Resize video to open the editor on Frame, where you can choose Fit or Center, custom pixel dimensions, or a blurred background.
3
Preview the framed picture on the canvas and press Export to download the MP4.

Changing video aspect ratio without distorting the picture

Audo’s online video resizer changes the aspect ratio and pixel dimensions of MP4, MOV, MKV, WebM, and AVI videos up to 2 GB without an account, with the first 10 minutes free, 10 times a day, and no sign-up. Social platforms each expect their own canvas shape—9:16 vertical for TikTok, Reels, and YouTube Shorts, 4:5 or 1:1 for Instagram and LinkedIn feeds, and 16:9 for YouTube and presentations.

Instead of stretching your footage to fit a new shape, Audo preserves the original aspect ratio of your camera or screen recording. You can either letterbox the whole image over a soft blurred backdrop or zoom and position the frame so your subject fills the screen.

Questions

How do I change video aspect ratio for TikTok, Reels, Shorts, or Instagram?

Add your clip above, pick TikTok, Reels, or Shorts for vertical 9:16, Square for 1:1, Instagram for 4:5 portrait, or YouTube for 16:9 widescreen, and press Resize video. The editor opens on Frame with your video fitted to that aspect ratio and platform safe-zone guides available to check.

How are Fit and Center fill different when resizing a video?

Fit keeps 100% of your original picture visible inside the new aspect ratio and fills the extra space at the top/bottom or sides with a blurred copy of your video or a solid color. Center enlarges the picture until it fills the entire target frame, cropping the outer edges evenly.

Can I change video resolution to exact custom pixel dimensions?

Yes. In the Frame panel under More, choose Custom and enter exact even width and height dimensions in pixels (up to 7680×4320). That is helpful when a presentation template, website hero banner, or ad spec requires fixed pixel dimensions.

Can the empty bars have a blurred or colored background?

Yes. When using Fit mode so nothing gets cut off, choose a blurred video background (with adjustable blur strength) or pick any solid hex color such as #000000 or #ffffff to match your brand or slide deck.

When should I use Horizontal to vertical video instead of Resize video?

Resize video applies one consistent frame layout across the clip—ideal for slides, product demos, and stationary speakers. If people move around or the camera cuts between speakers in a landscape interview, use Horizontal to vertical video so auto reframe tracks whoever is talking shot by shot.

Does resizing a video change the audio?

No. Your soundtrack stays synchronized at its original speed and duration while the picture is reformatted into the new frame.

Is it free?

Yes. Audo processes the first 10 minutes free, 10 times a day, without an account. The whole file costs $0.01 a minute ($0.60 an hour), charged only on success. No subscription. See pricing.

More tools

All tools

For AI assistants and developers

Ask ChatGPT, Claude, or a coding agent to do this for you, or call it from your own code. When an agent's free result is cut short, it gives you a link to finish the whole file, no sign-up.

Show the free API call

Free API · no key

curl -F file=@clip.mp4 https://audo.ai/api/try/resize-video -D response.headers -o response.body