Video Resizer
Resize and crop videos for TikTok (9:16), Instagram (1:1), and YouTube (16:9) with smart fit modes.
Click to select or drag & drop video
Resize video to 9:16 vertical (TikTok/Reels), 1:1 square (Instagram), or 16:9 widescreen with smart fit & crop modes.
How to use Video Resizer
- 1Upload your video file (MP4, WebM, MOV, MKV, or AVI).
- 2Select an aspect ratio preset: 9:16 Vertical (Reels/TikTok/Shorts), 1:1 Square (Instagram Feed), 4:5 Portrait, or 16:9 Landscape (YouTube).
- 3Choose your fit mode: 'Fit' (adds clean letterbox bars to show entire video) or 'Fill' (smart center crop to eliminate black bars).
- 4Click 'Render & Download' to process the video locally with hardware acceleration.
- 5Preview the resized video and download with original stereo audio preserved.
Key Features & Highlights
- •Social Media Aspect Ratio Presets: 9:16 (TikTok / Reels / Shorts), 1:1 (Instagram), 4:5 (Portrait Feed), and 16:9 (YouTube).
- •Fit vs Fill Options: Keep the entire video frame with letterboxing or crop the center to fill the screen without black bars.
- •Synchronized Stereo Audio: Automatically preserves and aligns the original audio track throughout the conversion.
- •GPU Hardware Acceleration: Real-time rendering via HTML5 Canvas and native browser video pipelines.
- •100% Private Client-Side Processing: Video files remain on your device and are never uploaded to third-party servers.
Understanding Video Resizer
Frequently Asked Questions
What is the best aspect ratio and resolution for TikTok, Instagram Reels, and YouTube Shorts?
The universal standard for short-form vertical video is a 9:16 aspect ratio at 1080×1920 pixels. Our '9:16 Vertical' preset automatically scales and centers your video to these exact dimensions so it displays full-screen on mobile without black bars or letterboxing.
What is the difference between 'Fit' (Letterbox) and 'Fill' (Crop)?
'Fit' scales the video so that 100% of the original content is visible, adding black or colored letterbox bars on the top/bottom or sides if the aspect ratios differ. 'Fill' scales the video until it completely fills the target frame, center-cropping the edges so no black bars appear.
Will resizing stretch or distort my video?
No. Our video resizer enforces strict proportional scaling, ensuring your actors, text, and graphics retain their natural proportions without horizontal squishing or vertical stretching.
Does resizing videos affect audio synchronization?
No. The audio stream is captured, resampled, and synchronized frame-for-frame with the resized video stream using the Web Audio API and MediaRecorder, guaranteeing that dialogue and music stay perfectly in sync.
Are my personal videos uploaded to a cloud server?
No. Video decoding, canvas re-scaling, and encoding run 100% inside your local web browser. Your video never leaves your computer or phone.
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