Change Aspect Ratio of Video

Free online tool to change video aspect ratio. Convert 16:9 to 9:16 for Instagram, TikTok. Change to 4:3, 1:1 square, 21:9 ultrawide. Crop, pad, or stretch video.

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About Change Aspect Ratio

Cross-platform creators live this nightmare: shoot once in 16:9 horizontal, then need 9:16 for TikTok/Reels/Shorts, 1:1 for Instagram feed, 4:5 for LinkedIn carousel, 21:9 for cinematic teasers. Each platform downrates videos that don't match its native aspect, hurting reach. This tool reshapes any video to any target ratio using ffmpeg.wasm in your browser: Crop fills the frame and discards edges (best when the subject is centered), Pad adds letterbox/pillarbox bars or a blurred background fill (preserves all content, ideal for landscape-to-portrait conversion of interview footage), or Stretch warps to fit (rarely correct, but useful for forced framing). Supports custom width:height ratios beyond presets, output quality control, and standard formats. All processing happens client-side via WebAssembly — no upload, no watermark, no cloud quota. See also our Compress Video and Video to GIF.

What aspect ratios are supported?

Common ratios: 16:9 (YouTube), 9:16 (Instagram Stories/TikTok), 4:3 (Standard), 1:1 (Square), 21:9 (Ultrawide), 3:4 (Vertical 4:3). You can also set custom ratios.

What's the difference between Crop, Pad, and Stretch?

Crop: Fills the new frame by cutting edges (no distortion). Pad: Adds black bars to fit (keeps all content). Stretch: Distorts video to fit exactly (may look unnatural).

What are padding color options?

Black (classic letterbox/pillarbox), White (bright background), or Blurred (uses blurred video as background for aesthetic look).

Will this affect video quality?

The video will be re-encoded. Choose High quality for best results. Quality impact depends on chosen settings and target resolution.

Change Aspect Ratio of Video — Free online tool to change video aspect ratio. Convert 16:9 to 9:16 for Instagram, TikTok. Change to 4:3, 1:1 square, 21 — **Change Aspect Ratio of Video**

What is the file size limit?

Maximum file size is 100MB. This ensures smooth processing in your browser.

Can I preview before downloading?

Yes! After processing, you can preview the video with new aspect ratio before downloading.

Is my video file safe?

Absolutely! All processing happens in your browser using FFmpeg.wasm. Your video is never uploaded to any server.

How long does processing take?

Processing time depends on video length and settings. Typically 30-60 seconds for a 5-minute video.