Video Resizer
Change video resolution while keeping quality. Pick a preset or set custom dimensions.
100% private
Videos never leave your browser
Common presets
1080p, 720p, 480p, 360p
Custom size
Set any width and height
Drop video here
or click to browse
The video resizer lets you downscale (or upscale) a clip to an exact pixel size. It is most often used to meet platform requirements — for example, resizing a recorded screencast to 1080p for YouTube, or bringing phone footage down to 720p so it uploads faster on a slow connection.
You can lock the aspect ratio to avoid stretching, or set width and height independently when you need a fixed output (such as 1080×1080 square video for Instagram or 1080×1920 portrait for TikTok). The preview updates as you edit the numbers so you can see how the frame will be cropped or letterboxed.
Everything runs locally with WebCodecs. Your video is not uploaded, there is no watermark, and the output is produced in MP4 so it plays on virtually any device.
Video Resizer — Frequently Asked Questions
What video size should I use for Instagram, TikTok, or YouTube?
Instagram feed: 1080×1080 (1:1) or 1080×1350 (4:5). Instagram Reels / TikTok: 1080×1920 (9:16 vertical). YouTube Shorts: 1080×1920. YouTube landscape: 1920×1080 (16:9). Twitter: 1280×720 is the sweet spot for fast upload.
How do I resize a video without distorting it?
Keep the 'maintain aspect ratio' toggle on and only set one dimension — the other is auto-calculated so the image never squishes. For mismatched targets (square output from a landscape source), the tool letterboxes transparent padding instead of cropping.
Does resizing reduce video quality?
Downscaling stays sharp and is how most platform delivery works anyway. Upscaling can't recover detail that wasn't in the original — if you record at 720p, you can't make a true 1080p, just an interpolated one. Match or downscale from the source whenever possible.
What's the maximum output resolution?
4K (3840×2160) is supported on modern desktop browsers with enough memory. For most web and social delivery, 1080p is the practical ceiling — going higher rarely improves viewer experience because players downscale anyway.
Does the audio track survive the resize?
Yes. Audio is passed through unchanged — only the video stream is re-encoded at the new resolution.
Is my video uploaded anywhere?
No. The resize runs entirely in your browser with WebCodecs. Your file never leaves your device.
What video size should I use for Instagram, TikTok, or YouTube?
Instagram feed: 1080×1080 (1:1) or 1080×1350 (4:5). Instagram Reels / TikTok: 1080×1920 (9:16 vertical). YouTube Shorts: 1080×1920. YouTube landscape: 1920×1080 (16:9). Twitter: 1280×720 is the sweet spot for fast upload.
How do I resize a video without distorting it?
Keep the 'maintain aspect ratio' toggle on and only set one dimension — the other is auto-calculated so the image never squishes. For mismatched targets (square output from a landscape source), the tool letterboxes transparent padding instead of cropping.
Does resizing reduce video quality?
Downscaling stays sharp and is how most platform delivery works anyway. Upscaling can't recover detail that wasn't in the original — if you record at 720p, you can't make a true 1080p, just an interpolated one. Match or downscale from the source whenever possible.
What's the maximum output resolution?
4K (3840×2160) is supported on modern desktop browsers with enough memory. For most web and social delivery, 1080p is the practical ceiling — going higher rarely improves viewer experience because players downscale anyway.
Does the audio track survive the resize?
Yes. Audio is passed through unchanged — only the video stream is re-encoded at the new resolution.
Is my video uploaded anywhere?
No. The resize runs entirely in your browser with WebCodecs. Your file never leaves your device.