A YouTube video resizer for clips that aren’t 16:9
YouTube’s standard frame on a computer is 16:9. Footage that isn’t — a phone video, a square clip, an old 4:3 recording or an odd-sized screen capture — still plays, but the player surrounds it with empty padding. This YouTube video resizer builds a proper 16:9 file at 1080p, 1440p or 4K and lets you decide what fills the sides: a blurred, darkened copy of the footage, a colour, or nothing at all because the picture is cropped to fill the frame.
It also follows the main points of YouTube’s recommended upload settings: H.264 video at the suggested bitrate for the resolution, AAC sound at 48 kHz and 384 kbps stereo, in an MP4 with its index at the front. The work is done in your browser by the Mediabunny library (MPL-2.0, loaded unmodified) and WebCodecs — unreleased videos never leave your computer.
How to resize a video for YouTube
- Drop the video on the upload area and check its resolution, frame rate, codecs and length.
- Choose a resolution: “1080p HD · 1920 × 1080” for most videos, 1440p or 4K only when the source has that much detail.
- Choose the fill: Blurred video keeps the full picture with soft sides, Colour gives clean bars, Nothing — crop fills the frame.
- When cropping a tall video, drag the preview up or down, or set keyframes so the crop follows the subject.
- Press “Make YouTube video”, check the result, then “Download MP4” and upload it in YouTube Studio.
YouTube Video Resizer features
16:9 at standard resolutions
1280 × 720, 1920 × 1080, 2560 × 1440 and 3840 × 2160 — the 16:9 sizes in YouTube’s resolution list.
YouTube’s recommended bitrates
8, 16 and 40 Mbps for 1080p, 1440p and 4K, raised by half automatically for 48–60 fps footage.
48 kHz AAC sound
Audio is saved as stereo AAC at 48 kHz and 384 kbps, YouTube’s recommendation for stereo.
Blurred or plain sides
Fill the frame with a soft copy of the video, a solid colour or a gradient — or crop instead.
Upload limit checks
Warnings for the 15-minute limit on unverified accounts and the 12-hour, 256 GB maximum.
Letterboxing, pillarboxing and what YouTube recommends
Letterboxing is bars above and below a picture that is wider than the frame; pillarboxing is bars at the sides of a picture that is narrower, such as a phone video in a 16:9 player. YouTube’s help centre says its player automatically changes to suit your video and the viewer’s device, and advises against adding padding or black bars to the video file, because baked-in bars stop the player from adapting. So if your video is already 16:9 or you are happy with the player’s own framing, upload it as it is.
Resize when you want a specific look the player can’t give you: blurred sides instead of plain space around a phone clip, a full-frame crop of a tall recording, a consistent 16:9 frame for a compilation of mixed clips, or a standard 1920 × 1080 file from an odd-sized or unusual-codec source. For vertical clips of up to three minutes, consider posting them as Shorts with the Shorts resizer instead.
YouTube resolutions and recommended bitrates
Figures for 1080p and above are YouTube’s recommended SDR upload bitrates as of 2026; the 720p row is this tool’s own setting. “Smaller file” halves the bitrate and “High” raises it by half.
| Resolution | Pixels (16:9) | Bitrate, 24–30 fps | Bitrate, 48–60 fps |
|---|---|---|---|
| 720p | 1280 × 720 | 5 Mbps (this tool) | 7.5 Mbps (this tool) |
| 1080p | 1920 × 1080 | 8 Mbps | 12 Mbps |
| 1440p | 2560 × 1440 | 16 Mbps | 24 Mbps |
| 2160p (4K) | 3840 × 2160 | 35–45 Mbps | 53–68 Mbps |
Practical tips
- Don’t upscale for the sake of it: a 720p phone clip turned into 4K is bigger, not sharper. Pick the resolution closest to your source.
- Keep the frame rate you recorded — YouTube asks for content to be uploaded at its original frame rate, and this tool doesn’t change it (except to cap anything above 60 fps).
- Trim long recordings first with the video cutter; the whole result is built in your browser’s memory, so 4K files need a well-equipped computer.
- Finish the upload with a 1280 × 720 thumbnail from the YouTube thumbnail resizer, and embed the video with the YouTube embed generator.
Sources (checked October 2026)
- YouTube Help — Recommended upload encoding settings (MP4 fast start, H.264, AAC-LC 48 kHz, bitrates)
- YouTube Help — Video resolution & aspect ratios (16:9 standard, player resizing, avoid padding)
- YouTube Help — Upload videos longer than 15 minutes (256 GB or 12 hours)
YouTube Video Resizer FAQ
What size should a YouTube video be?
16:9, most commonly 1920 × 1080 (1080p). YouTube’s list also includes 1280 × 720, 2560 × 1440 and 3840 × 2160 (4K). This YouTube video resizer makes any of them.
Should I add black bars to a vertical video before uploading it to YouTube?
YouTube recommends not adding padding or black bars, because its player adapts to your video’s shape. Use this tool when you want blurred sides or a crop instead, or a uniform 16:9 file for a compilation.
What bitrate does YouTube recommend for 1080p?
8 Mbps for 24–30 fps and 12 Mbps for 48–60 fps (SDR). The “Standard” setting here follows that automatically.
What is the maximum YouTube upload size and length?
256 GB or 12 hours, whichever is less. Until your account is verified, videos are limited to 15 minutes.
Can I make a 4K YouTube video from 1080p footage?
You can, but it adds no real detail and takes much longer to encode. The tool shows how much the picture is enlarged before you start.
Is my video uploaded to your server?
No. The resizing and encoding happen on your computer; you upload the finished MP4 to YouTube yourself.