How to Resize a Video for YouTube Shorts

Getting your video to look right on YouTube Shorts can feel frustratingly complicated, but it's simpler than you think once you know the rules. A video that’s even slightly off-format can get ugly black bars, be cropped awkwardly, or worse, not even register as a Short. This guide walks you through the exact dimensions for YouTube Shorts and provides step-by-step instructions for resizing your videos using tools you likely already have.

Understanding YouTube Shorts Specifications

Before you start resizing, you need to know the target. For YouTube to recognize your video as a Short, it must meet three specific criteria: aspect ratio, resolution, and length. Getting these right is the most important part of the process.

The Core Requirements for YouTube Shorts

Think of these as the non-negotiable rules for your video file. If you meet these, you're on the right track.

• Aspect Ratio: The video must be vertical, with a 9:16 aspect ratio. This is the standard tall, skinny format you see on your phone. A square (1:1) video may sometimes be picked up, but 9:16 is the official and most reliable format.
• Resolution: The recommended resolution is 1080x1920 pixels. While YouTube might accept other vertical resolutions, this is the standard for high-definition quality and what most modern smartphones shoot in naturally when held vertically.
• Length: Your video must be 60 seconds or less. Even a video that's 61 seconds long will be treated as a regular YouTube video, not a Short. For best performance, aim for the sweet spot between 15 and 59 seconds.
• File Format: Standard video formats like .MP4 and .MOV are your best bet. Most editing tools and cameras export to MP4 by default, so you generally won't have to worry about this.

Why You Can't Just Upload a Horizontal Video

So, what happens if you ignore the specs and upload a standard horizontal (16:9) video? YouTube’s system will try to make it fit, but the results are rarely ideal. Here are the common problems you'll encounter:

1. Awkward Automatic Cropping: YouTube might try to "center-crop" your horizontal video to create a vertical 9:16 frame. This means it will chop off the left and right sides of your shot. If your main subject isn't perfectly centered, they could get cut out of the frame entirely, ruining the video.

2. Unsightly Black Bars (Pillarboxing): Instead of cropping, YouTube might default to placing your horizontal video in the middle of a vertical frame and adding black bars at the top and bottom to fill the empty space. This is called "pillarboxing," and it immediately signals to viewers that the content wasn't formatted correctly. It makes your content look unprofessional and wastes valuable screen real estate, causing viewers to scroll away instantly.

3. It Doesn't Get Picked Up by the Shorts Algorithm: The algorithm that feeds content into the Shorts shelf and feed is looking specifically for videos that meet the vertical format criteria. A horizontal video, even if it’s under 60 seconds, will likely be categorized as a standard video and won't get the discoverability benefits of being a Short.

Properly resizing your video signals to both YouTube and your audience that your content is intentionally made for this platform, ultimately leading to better engagement and reach.

How to Resize a Video for YouTube Shorts (3 Methods)

Resizing a video is straightforward with the right tools. Whether you want a quick fix on your phone or a more precise edit on your desktop, there’s a method for you. We’ll cover three popular approaches from easiest to most advanced.

Method 1: Using Your Smartphone's Built-in Editor

For quick edits, you often don't need to download another app. Your phone’s native photo and video editor can handle basic resizing and cropping, making it perfect for last-minute adjustments.

For iPhone Users (Photos App):

1. Open the Photos app and find the video you want to resize.
2. Tap "Edit" in the top-right corner.
3. Tap the Crop icon at the bottom (it looks like a square with rotating arrows).
4. In the top-right corner, tap the Aspect Ratio icon (it looks like stacked rectangles).
5. From the bottom menu, scroll to the right and select the 9:16 vertical option.
6. Drag the video within the frame to position your subject correctly, ensuring nothing important gets cut off.
7. Tap "Done" to save the changes. Your video is now perfectly formatted for Shorts.

For Android Users (Google Photos or Gallery App):

The exact steps can vary slightly by manufacturer (Samsung, Google Pixel, etc.), but the process is generally similar.

1. Open your Gallery or Google Photos app and select your video.
2. Tap the "Edit" button.
3. Look for a "Crop" or "Frame" option.
4. Find the aspect ratio settings. It might be represented by an icon or simply text. Select 9:16.
5. Adjust the frame to center your content.
6. Save your new-and-improved vertical video.

Method 2: Using Free Online Video Editors

If you need a bit more control - like adding text overlays or combining clips - free online tools are an excellent option. Tools like Canva and CapCut's online editor are incredibly popular and designed for social media content creation.

Step-by-Step with a Tool like Canva:

1. Go to the website (e.g., Canva.com) and create a free account if you don't have one.
2. On the homepage, click "Create a design" and search for "YouTube Shorts." Canva has a pre-made template with the correct 1080x1920 dimensions.
3. Once you have your blank vertical canvas, go to the "Uploads" tab on the left-hand sidebar and upload your video file.
4. Drag your uploaded video onto the canvas. It will likely not fill the full frame.
5. Click and drag the corners of the video to scale it up until it fills the entire 9:16 canvas. Alternatively, right-click the video and select "Set video as background" to have it automatically snap-to-fit.
6. Play the video back to see if your subject stays in frame. You can double-click the video to pan it left or right, ensuring the most important action is visible.
7. Once you're happy with the positioning, click the "Share" button in the top-right, then "Download." Make sure the file type is set to MP4 and download your resized video.

Method 3: Using Desktop Video Editing Software

For content creators who already use dedicated editing software like Adobe Premiere Pro, Final Cut Pro, or DaVinci Resolve, creating perfectly formatted Shorts is just a matter of setting up your project correctly from the start.

The General Workflow for Premiere Pro/DaVinci Resolve:

1. Create a New Sequence/Timeline: Instead of using a default 16:9 preset, go into your sequence/timeline settings. Set the frame size to a custom resolution of 1080 (width) by 1920 (height). This creates your vertical canvas.
2. Import Your footage: Drag your horizontal video clip onto this new vertical timeline. It will appear small, likely with black bars at the top and bottom.
3. Scale and Reposition: Select the clip on your timeline and go to the Effects Controls panel. Increase the "Scale" property until the video's width fills the screen. You'll probably need to scale it up to around 200%, depending on the original resolution.
4. Reframe the Shot (Keyframing): This is where desktop software shines. Your subject likely moves around in the original horizontal frame. By using keyframes on the "Position" property, you can track the subject, essentially creating a fake camera operator who pans left and right to follow the action. This keeps your subject centered throughout the Short and makes repurposed content feel dynamic instead of static.
5. Export: Export your timeline using standard H.264 settings. Your final file will be a perfectly formatted 1080x1920 pixel MP4, ready for upload.

Pro Tips for Creating Standout YouTube Shorts

Simply resizing your video is only half the battle. To create Shorts that capture attention and build your brand, you need to optimize the viewing experience. Here are a few final thoughts to keep in mind:

• Mind the Safe Zones. The YouTube Shorts interface overlays a few elements on your video: your channel name, the video title, and the like/comment/share icons are all at the bottom. Keep your most important visual elements and any text overlays away from the bottom 15% and top edge of the screen to prevent them from being obscured.
• Add Value with text. Since many people watch videos on mute, adding on-screen captions or text callouts is a great way to keep them engaged. It provides context and keeps the story moving forward even without sound.
• Create a strong hook. The first one to three seconds are everything. Your opening must grab attention or pose a question that makes the viewer want to see the answer. Don't waste time with slow intros or logos. Get straight to the value.
• Use the Space creatively. When converting a horizontal video, don't just zoom and crop. Get creative by placing the main clip at the top and adding a relevant caption or title card at the bottom of the 9:16 frame. This gives context and fills the space in a visually appealing way.

Final Thoughts

Resizing a video for YouTube Shorts isn't a complex technical challenge, it’s about knowing the 9:16 format and choosing the tool that best fits your workflow, whether it's your phone or professional desktop software. Taking a few extra minutes to properly format your video makes a massive difference in how it's perceived by viewers and promoted by the algorithm.

That said, constantly worrying about aspect ratios and resizing videos for every platform can be a real time drain, especially when you're managing Shorts, Reels, and TikToks. At Postbase, we designed our platform from the ground up to solve this exact problem. Because we built our scheduler with a short-form video-first approach, you can upload your content once and trust it will post natively and correctly across all your channels without weird formatting issues or compression headaches.