Tool
Enter one dimension and get the other. Pick from common ratios or set your own.
YouTube videos are 16:9. Instagram posts are 1:1 or 4:5. Stories and Reels are 9:16. When you're designing a banner and the client gives you a width, you need the height. When you're exporting video for different platforms, you need dimensions that match. This calculator does the math faster than reaching for a calculator app.
| Ratio | Common Use | Typical Resolution |
|---|---|---|
| 16:9 | YouTube, TV, presentations | 1920×1080, 2560×1440 |
| 4:3 | Classic TV, iPad | 1024×768, 2048×1536 |
| 1:1 | IG posts, profile pics | 1080×1080 |
| 4:5 | IG portrait posts | 1080×1350 |
| 9:16 | Stories, Reels, TikTok | 1080×1920 |
| 21:9 | Ultrawide monitors, cinema | 2560×1080, 3440×1440 |
| 3:2 | Camera photos, MacBook | 2160×1440, 6000×4000 |
Upload a video with the wrong aspect ratio and the platform will auto-crop or add black bars. That thumbnail you spent an hour on gets clipped in half. Subtitles end up outside the frame. On websites, banners with the wrong ratio get squished, stretched, or leave awkward whitespace in responsive layouts. Getting the ratio right before you start saves you from fixing it after.
YouTube thumbnails are 1280×720 (16:9). Instagram posts: 1080×1080 or 1080×1350. Facebook cover photos: 820×312 on desktop, 640×360 on mobile. Twitter/X headers: 1500×500 (3:1). LinkedIn covers: 1584×396. These pixel counts get updated occasionally, but the ratios rarely change. Remembering the ratio is more useful than memorizing pixel values — just plug the width into this calculator and get the matching height.