Which aspect ratio is best for TikTok and Instagram Reels?

9:16 Vertical is the standard vertical fullscreen ratio for TikTok, Reels, and YouTube Shorts.

What is the difference between "Fit" and "Fill"?

"Fit" shows the entire video without cropping by adding subtle borders. "Fill" scales the video to occupy every pixel without black bars.

Video 100% Client-Side

Change video aspect ratio for TikTok (9:16), YouTube (16:9), Instagram (1:1 or 4:5) with fit & fill modes.

Zero Upload

Never leaves browser

Instant Speed

WASM accelerated

or click to browse from your device

Transform landscape videos into vertical 9:16 for TikTok, Reels, and Shorts

Support for 9:16 Vertical, 16:9 Landscape, 1:1 Square, and 4:5 Feed formats

Two framing modes: "Fit with Letterbox" or "Fill & Crop" to avoid distortion

High 30fps canvas rendering pipeline with crisp image quality

100% In-browser conversion — no file uploads, completely private

Simple Workflow

Get results in three quick steps without any learning curve.

Select or drag your video file into the upload zone.

Choose 9:16 for TikTok/Reels, 16:9 for YouTube, or 1:1 for Instagram feeds.

Click "Resize Video" and download your newly formatted video instantly.

Need Help?

Everything you need to know about this tool.

Explore More

Reduce video file size without noticeable loss in visual quality. Fast client-side video compression.

Cut and trim video clips to custom start and end timestamps with live playback preview.

Convert MP4 and WebM videos to animated GIF images with custom FPS and resolution.

Preparing your tools and workspace. Please wait a moment.