Video Aspect Ratio Online Free – Letterbox 16:9, 9:16, 1:1

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Why change video aspect ratio?

Different platforms use different aspect ratios: 16:9 for YouTube and TV, 9:16 for TikTok and Reels, and 1:1 for some Instagram posts. This tool converts to the chosen ratio by letterboxing (fit with padding) so nothing is cropped.

Benefits

Platform-ready: Match 16:9, 9:16, 1:1, 4:3, or 3:4 for major platforms.
No cropping: Letterboxing keeps the entire image; padding fills the rest.
Blur background: A popular Reels look that avoids harsh black bars.
Format choice: Export MP4, WebM, or MOV while preserving quality.
Privacy: Processing happens in your browser; files never leave your device.

Padding background options

When the video doesn’t fill the target frame, you can choose how to fill the bars for a polished look.

Available options

Blur background: Fill padding using a blurred version of the frame. Adjust blur strength.
Solid color: Use any color (default black) for consistent branding.
Image background: Upload an image to fill padding behind the video.
Mirror edges: Extend the frame using mirrored edges (no extra assets).
Black: Classic letterbox bars—simple and neutral.

Common aspect ratios

Choose the ratio that matches your target platform or use case.

Available ratios

16:9 (Landscape): Widescreen for YouTube, TV, and desktop playback.
9:16 (Portrait / Reels): Vertical for TikTok, Reels, and Stories.
1:1 (Square): Square for some Instagram feed posts.
4:3 (Standard): Traditional ratio used in older TV and cameras.
3:4 (Portrait): Portrait ratio used for some social and mobile layouts.

How video aspect ratio change works

The tool letterboxes your video: it scales the image to fit inside the target aspect ratio and adds padding so the output has the exact ratio without cropping.

Processing steps

Upload & decode: The video is decoded in your browser.
Scale to fit: Frames are scaled to fit inside the target dimensions without stretching.
Letterbox & padding: Padding is added as needed; you choose blur, black, solid color, image, or mirror edges.
Re-encode & output: Frames are encoded to MP4/WebM/MOV with optional bitrate preservation.
Client-side processing: Everything happens locally; videos never leave your device.

Frequently Asked Questions

What does letterboxing mean?

The video is scaled to fit inside the target aspect ratio and padding (bars) is added as needed so the output has the exact ratio (e.g. 16:9) without cropping. You can choose black, blur, solid color, image, or mirror edges for the padding.

What is blur background for letterboxing?

Blur background fills the padding with a blurred version of the same video frame. It’s popular for Reels and vertical content because it looks natural instead of black bars. You can adjust blur strength.

What padding background options are available?

Black, blur, solid color, image background, or mirror edges.

Is my video data secure?

Yes. All processing happens in your browser. Your videos never leave your device.

What video formats can I output?

You can export as MP4 (H.264), WebM (VP9), or MOV (H.264). Input format is used by default when supported. Fallback encoder outputs MP4 only.

Which aspect ratio should I use for YouTube / TikTok / Instagram?

YouTube/TV: 16:9. TikTok/Reels/Stories: 9:16. Instagram feed: 1:1 or 4:5. This tool letterboxes to the chosen ratio so nothing is cropped; blur background is a popular Reels look.

Does letterboxing reduce quality?

The video is re-encoded with padding to the target dimensions. Quality is preserved as much as possible with efficient encoding and optional bitrate handling. The visible picture is not cropped or stretched.