Video aspect ratios explained: 16:9, 9:16, 4:5 and 1:1
Why the same video appears with black bars, gets cropped, or fills the screen — and which shape each platform expects.
2 min read · Updated
Aspect ratio is the shape of the video: its width compared with its height. Get it wrong and a video lands with black bars, a cropped-off head, or a tiny box in the middle of a phone screen. Get it right and it simply fills the screen it's watched on.
The ratios you'll meet
Almost every video online uses one of these shapes:
- 16:9 (landscape) — YouTube videos, TVs, laptops. 1920 × 1080 is the standard 1080p frame.
- 9:16 (vertical) — YouTube Shorts, Instagram Reels, TikTok, Stories. 1080 × 1920 is the common size.
- 4:5 (tall portrait) — Instagram and Facebook feed posts; takes up more of a phone screen than square.
- 1:1 (square) — older Instagram posts and some ads.
- 21:9 and wider — cinematic films, often shown on 16:9 screens with bars above and below.
Aspect ratio and resolution aren't the same thing
Resolution counts pixels; aspect ratio describes the shape they make. A vertical Short at 1080 × 1920 and a landscape video at 1920 × 1080 have exactly the same number of pixels and the same sharpness — just turned 90 degrees. Calling the vertical one “1080p” is correct: the short side is 1080 pixels.
Why black bars appear
When a video's shape doesn't match the screen, the player has two choices: fit the whole video and fill the gaps with black bars, or fill the screen and crop some of the picture off. Bars on the sides of a vertical video on a laptop, or above and below a widescreen film on a TV, are the player being careful not to cut anything off.
Bars that are part of the video itself — burned into the file — are a different matter. They usually come from a tool that forced a vertical video into a landscape frame. That's why good downloaders keep each video's original shape: the Shorts downloader and Instagram downloader never pad or crop.
Converting from one ratio to another
There's no lossless way to change a video's shape. You can only:
- Crop — cut the sides (or top and bottom) away. Works when the subject sits in the middle.
- Pad — add bars or a blurred background to fill the new shape. Keeps everything, looks less polished.
- Reframe — crop, but move the crop to follow the subject. Many editors and phone apps can do this automatically.
Starting from a higher resolution makes cropping far less painful: cropping a vertical frame out of a 4K landscape video still leaves a sharp result. 1080p vs 4K covers when that extra resolution is worth keeping.
Which ratio to use when posting
Use the platform's native shape: 16:9 for YouTube videos, 9:16 for Shorts, Reels and TikTok, 4:5 for Instagram and Facebook feed posts. Posting the wrong shape means the platform crops or pads it for you, usually worse than you would. Vertical video specs for Shorts, Reels and TikTok lists sizes and lengths for short-form platforms.