AI Video Resizer
Change your video's aspect ratio without cropping. AI expands the scene around your subject to fill 9:16, 16:9, 1:1 and more - ready for TikTok, YouTube Shorts, Instagram Reels and beyond. Add a prompt to guide how the new area is filled. Videos up to 30 seconds.
AI Video Resizer in Action
Watch how AI expands a landscape clip into a vertical 9:16 video - no cropping, no black bars.
How to Use Our AI Video Resizer
Resize and reframe your video to any aspect ratio in 3 simple steps
Upload Your Video
Drop your video into the resizer or paste a URL. MP4, MOV and WebM files up to 30 seconds and 100MB are supported.
Choose Target Aspect Ratio
Select from 7 aspect ratios - 16:9, 9:16, 1:1, 4:3, 3:4, 21:9, and 9:21 - optimized for YouTube, TikTok, Instagram, and more. Optionally add a custom prompt to guide the AI on how to reframe your scene.
Resize & Download
The AI video resizer intelligently reframes your video, expanding the scene to fit the new ratio. Preview the result and download it as an MP4.
Resize Videos for TikTok, Instagram, YouTube and More
Pick the aspect ratio for where your video will be posted. The AI fills the new space instead of cropping, so nothing important gets cut off.
TikTok
9:16Turn landscape footage into a full-screen vertical video instead of posting it with black bars above and below.
YouTube Shorts
9:16Repurpose moments from your long-form 16:9 videos as Shorts without cutting people or products out of the frame.
Instagram Reels & Stories
9:16Resize videos for Instagram without cropping. The scene is extended to fill the whole phone screen, edge to edge.
YouTube & Websites
16:9Convert vertical phone clips to widescreen for YouTube videos, landing pages and presentations - no blurred side bars.
Instagram & Facebook Feed
1:1 / 3:4Square 1:1 works for feed posts on most social platforms, and 3:4 matches the Instagram profile grid.
Ads for Every Placement
9:16 / 1:1 / 16:9Ad platforms ask for vertical, square and landscape versions. Create all three from one video instead of reshooting.
AI Video Expander (Video Outpainting): Extend the Frame Instead of Cropping
Need more room around your shot? The AI expands the video background beyond the original edges, so your clip fits the new aspect ratio and nothing gets cut off.
Expand the Video Background
The AI generates new scenery around your footage that matches its lighting, colors and movement, frame by frame. Your original shot stays in place in the middle.
Landscape to Portrait, and Back
Turn a 16:9 clip into a 9:16 vertical video by extending the frame above and below, or widen a vertical clip to 16:9 by extending the sides.
Tell the AI What to Add
Add an optional prompt to describe what should fill the new area, such as more sky, a wider room or a longer stretch of beach.
AI Aspect Ratio Changer for Videos
Change a video's aspect ratio online in one step. Pick the ratio you need and the AI reframes your clip to fit, adding new scenery where the frame grows instead of cropping or adding black bars.
Landscape to Vertical
16:9 → 9:16Use it as a vertical video converter: the AI adds new scenery above and below, so a widescreen clip fills a phone screen without losing its sides.
Vertical to Widescreen
9:16 → 16:9Turn a phone clip into a widescreen video. The AI fills the empty space on the left and right with matching scenery, and your whole original shot stays in the frame.
Landscape to Square
16:9 → 1:1Make a square version of a widescreen video. The AI adds space above and below, so you don't have to cut the edges off your shot.
Old 4:3 Footage to Widescreen
4:3 → 16:9Give older 4:3 recordings and screen captures a widescreen frame by extending the sides, without black pillarbox bars.
Widescreen to Cinematic
16:9 → 21:9Widen a 16:9 shot into an ultra-wide 21:9 frame for a cinematic look, with the extra width generated to match the scene.
Story to Feed Post
9:16 → 3:4Reuse a full-screen story as a 3:4 portrait post for the Instagram feed and profile grid. The AI widens the frame on both sides to fit.
Why Choose Our AI Video Resizer
Resize videos smarter - AI-powered reframing that adapts your content without compromise
Keep Your Subject in Focus
AI intelligently detects and preserves your main subject while expanding the scene around it - no awkward cropping or lost details.
7 Aspect Ratios, Every Platform
Resize to 16:9, 9:16, 1:1, 4:3, 3:4, 21:9, and 9:21. One video, perfectly adapted for YouTube, TikTok, Instagram Reels, and more.
No Black Bars, No Watermark
Instead of padding your video with black or blurred bars, the AI generates matching scenery for the new area. Results download as clean 720p MP4s without a watermark.
Custom Prompt Control
Guide the AI with your own prompts - describe how you want the scene expanded and the AI follows your creative direction.
Frequently Asked Questions About AI Video Resizer
Everything you need to know about resizing and reframing videos with AI
Traditional resizing simply stretches or crops your video, which often cuts out important content. Our AI video resizer analyzes each frame, keeps your main subject in place, and expands the scene around it (also called video outpainting) to fill the new aspect ratio - keeping everything in frame without distortion.
Upload your 16:9 landscape video, choose 9:16 as the target aspect ratio and start resizing. Instead of cutting off the sides, the AI extends the scene above and below your footage, so the whole original shot stays visible in the new vertical video. The same works in reverse - pick 16:9 to turn a vertical clip into a landscape one.
Yes. When you choose a new aspect ratio, the AI extends the frame past the original edges and generates matching background for the new area, which is also called video outpainting. Pick a ratio wider than your clip to add space on the sides, or a taller one to add space above and below.
TikTok, Instagram Reels, Instagram Stories and YouTube Shorts all use vertical 9:16. Regular YouTube videos use 16:9. For feed posts, 1:1 square works on most platforms, and 3:4 matches the Instagram profile grid. Our resizer outputs 9:16 videos at 720x1280 and 16:9 videos at 1280x720.
Our AI video resizer supports 7 aspect ratios: 1:1 (Square), 16:9 (YouTube/Landscape), 9:16 (TikTok/Reels/Shorts/Portrait), 4:3 (Standard), 3:4 (Portrait), 21:9 (Ultra-wide), and 9:21 (Ultra-tall). Each is optimized for different social media platforms.
All resized videos are output at 720p (HD) resolution, whatever the resolution of your input video. Because the AI expands the scene rather than stretching pixels, your footage keeps its original proportions in the new aspect ratio.
Currently, the video resizer supports videos up to 30 seconds in length. This covers most social media content needs including TikTok, Instagram Reels, and YouTube Shorts.
You can upload MP4, MOV and WebM files up to 100MB. If your browser can't play a file, convert it to MP4 first. You can also paste a direct video URL instead of uploading a file.
Yes! Our video resizer supports custom prompts. You can describe how you want the AI to expand and reframe your scene, giving you creative control over the final result beyond just choosing an aspect ratio.
Yes. The same AI video resizer is available through the Veevid API and MCP server as the reframe mode. Send a video URL, the target aspect ratio and the clip length in seconds, check the exact cost with a free quote, then fetch the result when it's ready. API requests use the same credits as the website, from your account balance.
Resizing costs 12 credits per second of video, so a 10-second clip costs 120 credits. The exact cost is shown before you start, based on your video's length. Credits come with a subscription or a one-time credit pack.
Ready to Resize Your Video?
Transform your video to any aspect ratio with AI-powered reframing that keeps your subject in focus - no cropping, no black bars.