Platform presets
Move between 16:9, 1:1, and 9:16 canvases with predictable dimensions.
Free Tool
Video Canvas Extender
Add letterbox or pillarbox padding to change your video's aspect ratio — 1:1 for Instagram, 9:16 for Stories, 16:9 for YouTube, 21:9 for cinematic. Choose any padding color. All processing is in-browser.
Watch the workflow
Add letterbox or pillarbox padding to change aspect ratio — 1:1, 9:16, 16:9, 21:9
Target aspect ratio
#000000
Drop a video file or click to upload
MP4 · WebM · MOV — padding added in a background worker
Common use cases
1:1 (Square) — required for Instagram feed posts and some social platforms. Adds top/bottom bars to horizontal video.
9:16 (Vertical) — TikTok, Instagram Reels, YouTube Shorts. Adds side bars to horizontal footage.
16:9 (Widescreen) — YouTube, Vimeo, presentations. Adds top/bottom bars to vertical footage.
21:9 (Cinematic) — adds black bars for a wide-screen film look.
Frequently asked questions
Does it crop my video?
No — nothing is cropped. The tool adds padding (blank canvas area) around your video to reach the target aspect ratio. Your video is centered with padding on two sides.
Can I choose any padding color?
Yes. Use the color picker to choose any solid color, or click White or Black for quick access. The color fills all added canvas area uniformly.
What format is the output?
Output is WebM (VP9). To convert to MP4, use the Video Format Converter tool afterwards.
Can I use a custom aspect ratio?
Yes. Select "Custom…" in the ratio buttons and enter any width and height values. For example, 2:1 or 3:2 are valid custom ratios.
Does it affect the audio?
No. The audio track from your source video is preserved exactly in the output.
Aspect reframing
Fit a new platform without cutting away the source frame
Letterbox and pillarbox padding place the full clip inside square, vertical, or widescreen canvases with visible framing guides.
No crop
Source-frame promise
Full frame retained
Padding changes the canvas around the clip rather than zooming into it.
Background choice
Use a deliberate bar colour that supports the destination and source imagery.
Know before you process: Padding preserves every source pixel but uses less of the destination frame; use the editor when a creative crop is preferable.
Ready to try it?
Free, private, no signup. 1:1, 9:16, 16:9, 21:9 and custom.
Extend video canvas →