Every social platform has its own preferred video dimensions. A landscape video filmed at 16:9 for YouTube looks wrong letterboxed on Instagram Stories. A square clip for Facebook has black bars on TikTok. Cropping and resizing a video to the correct aspect ratio before uploading is one of the most effective things you can do to improve how your content looks on each platform — and it can be done free in your browser without any software.
Aspect Ratio vs. Resolution: What’s the Difference?
Aspect ratio is the proportional relationship between a video’s width and height — expressed as two numbers like 16:9 or 9:16. Resolution is the actual pixel count (e.g. 1920×1080). You can change resolution without changing aspect ratio (scaling), or change aspect ratio without changing resolution (cropping). Most platform optimisation tasks require both: crop to the right ratio, then scale to the platform’s recommended pixel dimensions.
Aspect Ratios by Platform: Quick Reference
| Platform / Format | Aspect Ratio | Resolution | Notes |
|---|---|---|---|
| YouTube (standard) | 16:9 | 1920×1080 | Native player ratio — no black bars |
| YouTube Shorts | 9:16 | 1080×1920 | Full-screen vertical |
| Instagram Feed | 1:1 or 4:5 | 1080×1080 or 1080×1350 | 4:5 uses more screen space |
| Instagram Reels / Stories | 9:16 | 1080×1920 | Full-screen vertical |
| TikTok | 9:16 | 1080×1920 | Horizontal clips are penalised |
| Facebook Feed | 16:9 or 1:1 | 1280×720 minimum | Square performs well in feed |
| 16:9 or 1:1 | 1920×1080 preferred | See LinkedIn video guide | |
| Twitter / X | 16:9 or 1:1 | 1280×720 minimum | Up to 2:20 runtime |
How to Change a Video’s Aspect Ratio Free in Your Browser
VideoToolShack’s Video Trimmer handles both cropping (removing content from the frame edges) and the most common aspect ratio conversions. The workflow below applies to any direction of change: landscape to portrait, landscape to square, or portrait back to landscape.
Before changing the aspect ratio, cut your video to the segment you want to repurpose. Use the Video Trimmer to set your in and out points. Working on a shorter clip makes subsequent steps faster and produces a smaller output file. See the trimming guide for precise cut-point tips.
The free Format Converter lets you set a target resolution when converting. Select MP4 as the output format and enter the pixel dimensions for your target platform. The converter handles the scaling pass to match those dimensions.
When you change aspect ratio, you have two choices for how to handle the parts of the frame that don’t fit the new shape: letterbox (add black bars to fill the unused space — no content is lost) or crop to fill (cut the edges of the frame so the new ratio is filled completely — some content is lost at the edges). For social media, crop-to-fill generally looks more professional.
After converting to the new dimensions, run the output through the Video Compressor if you need to reduce file size for platform upload limits. Most platforms accept files up to 500 MB–4 GB, so compression is usually optional at this stage.
Converting 16:9 to 9:16 (Landscape to Vertical)
This is the most common repurposing task — taking a YouTube-style landscape video and adapting it for Reels, Shorts, or TikTok. When cropping a 16:9 source to 9:16, you retain roughly 31% of the original width. A 1920×1080 source cropped to 9:16 produces a 607×1080 frame, which is then scaled up to 1080×1920.
Converting 16:9 to 1:1 (Landscape to Square)
Square video performs well in social media feeds across Facebook, Instagram, and LinkedIn because it occupies more vertical screen space than 16:9. Cropping a 16:9 source to 1:1 retains the central 56% of the frame width. A 1920×1080 source cropped to square produces a 1080×1080 output with the left and right edges removed.
Square is a useful intermediate format if you want one crop that works reasonably well on both landscape-friendly platforms (Facebook, LinkedIn) and square-optimised feeds (Instagram). It avoids the severe content loss of a full 9:16 crop while still filling the feed frame better than a letterboxed 16:9.
Adding Captions After Resizing
When repurposing content for vertical or square formats, adding burned-in captions is strongly recommended. Most social platforms autoplay videos silently, and captions ensure your content communicates even without audio. Use the Add Subtitles tool to embed captions after your resize is complete — always caption last, after the crop and resize, so text positioning is correct for the final frame dimensions.
- YouTube standard: keep native 16:9 — no conversion needed
- YouTube Shorts / TikTok / Reels / Stories: 9:16 — crop landscape source to centre column
- Instagram Feed / Facebook Feed: 1:1 or 4:5 — square or mild portrait crop
- LinkedIn: 16:9 preferred — see the LinkedIn video format guide
- After cropping: add captions with Add Subtitles — always after resize, not before
- File too large after resizing: compress with Video Compressor
For guidance on the best output format and codec settings for each platform after resizing, see the full guide on best video format for web and social media. For repurposing a longer video into short vertical clips, see how to make YouTube Shorts from a longer video.