Aspect Ratio Changer

Resize videos for TikTok, Instagram & YouTube. 100% Client-Side.

Upload Video

Change aspect ratio locally. No upload needed.

Change Video Aspect Ratio Online - Resize for Instagram, TikTok, YouTube

Easily convert your videos to 9:16, 1:1, 16:9, or custom aspect ratios. Perfect for adapting content for TikTok, Instagram Reels, YouTube Shorts, and standard posts. 100% Free & Client-Side.

Optimized for Social Media

One-click presets for TikTok (9:16), Instagram Square (1:1), and YouTube (16:9).

Smart Fitting Options

Choose how your video fits the new frame: Cover (crop), Contain (add black bars/letterbox), or Fill (stretch).

No Quality Loss

High-quality resizing using advanced browser-based processing. Your video stays crisp.

Secure & Private

All processing happens on your device. Your videos are never uploaded to any server.

Stop struggling with complex editing software. Resize your videos instantly for any platform. Need to grab frames from your video? Try our Frame Grabber tool. Want to trim before resizing? Use our Video Trimmer first.

How to Resize Your Video

1

Upload Video

Select the video you want to resize. Supports MP4, WebM, MOV, and more.

2

Choose Aspect Ratio

Select a preset like 'Portrait (9:16)' or 'Square (1:1)', or enter custom dimensions.

3

Select Fit Mode

Choose 'Cover' to crop and fill the screen, 'Contain' to see the whole video with bars, or 'Fill' to stretch.

4

Download

Click 'Resize & Download' to save your new video file instantly.

Pro Tip: Use 'Cover' mode when converting landscape videos to vertical (TikTok/Shorts) to fill the whole screen, centered on the action.

Frequently Asked Questions

Will my video quality decrease?

We prioritize quality. However, 'Cover' mode crops pixels, and 'Fill' mode stretches pixels, which changes the visual fidelity. 'Contain' preserves the original image exactly.

Is this free?

Yes, 100% free and unlimited usage.

What is the best ratio for TikTok?

TikTok and Instagram Reels use 9:16 (Portrait).

Related Tools

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Frame Grabber

Extract frames from your videos as images

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Video Trimmer

Cut and trim videos with precision

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Format Converter

Convert videos between different formats

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