# Resize Video: Online Video Resizer & Aspect Ratio Changer

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

## How it works

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.

Tool: Resize video (`resize_video`). Price: 1 credit a minute — $0.01/min ($0.60/hr), with no subscription — of input for whole files, charged only when a job succeeds.

## Free API

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

Read response.headers and response.body before naming media. Handle 202, 200 JSON and errors with the complete response client at https://audo.ai/docs/api?utm_source=markdown&utm_medium=agent#responses.

Free for the first 10 minutes of each file, 10 times a day per person, with no key or account. Uploads up to 10 GB, 2 at once from one address. The response is the result itself; a job that runs longer than about 30 seconds returns 202 with a link to check on it. With an API key (`-H "Authorization: Bearer $AUDO_API_KEY"`), omitting free runs the whole file with credits if the balance covers it, otherwise the free portion if quota remains. Set free=true to prohibit spending; for paid whole files use free=false with an approved positive max_credits. A free result cut short comes with finishUrl (and the Audo-Finish-Url header when the response is the file itself): give it to the person, who pays there (from $5, no sign-up), and the whole file runs; keep checking the status link, whose finishedBy names the whole-file job and its own status link. Details: https://audo.ai/docs/api.md

## Options

Form fields with the same names as the MCP tool's inputs:

- `ratio`: Output aspect ratio. Default 9:16; custom needs width and height.
- `width`: Custom width in even pixels. Needs ratio custom.
- `height`: Custom height in even pixels. Needs ratio custom.
- `mode`: fit shows the whole picture with padding; fill crops to cover the frame.
- `zoom`: Enlarge the picture within the frame, 1 to 10. Default 1.
- `position_x`: Horizontal alignment in the frame, 0 left to 1 right. Default 0.5.
- `position_y`: Vertical alignment in the frame, 0 top to 1 bottom. Default 0.5.
- `background`: Padding background: solid color or a blurred copy of the video.
- `color`: Background color in six-digit hex, such as #ffffff.
- `blur`: Background blur amount, 1 to 100. Default 20.

## Languages

Any language: it works on the sound, not the words.

## From an assistant (MCP)

Add https://audo.ai/mcp and sign in (setup for each assistant: https://audo.ai/setup.md). The tool is `resize_video`:

> Resizes video to a ratio preset or explicit width and height. Fits with padding or fills by cropping, with zoom, horizontal and vertical position, and a solid color or blurred background. It costs 1 credit a minute of input, charged only if the job succeeds. Returns the result with download links, or job_id for get_job if it takes longer.

Example: "Use Audo to resize video from clip.mp4."

## 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

- Every tool: https://audo.ai/llms.txt
- OpenAPI: https://audo.ai/api/openapi.json
- This page for people: https://audo.ai/resize-video?utm_source=markdown&utm_medium=agent