Aspect Ratio Calculator
Calculate missing dimensions from aspect ratio or find the ratio from width and height. Presets for 16:9, 9:16, 1:1, 4:5 and more. Shows common resolutions. Free online tool.
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Smart PicksHow to use Aspect Ratio Calculator
Aspect Ratio Calculator — Calculate missing image or video dimensions from a ratio, or find the simplified ratio from any width and height. Includes presets for YouTube, TikTok, Instagram, and more.
- 1Select 'Calculate Dimension' to find width/height, or 'Find Ratio' to simplify a ratio.
- 2Click a preset ratio chip (16:9, 9:16, 1:1, etc.) or type a custom ratio.
- 3Enter the known dimension and click Calculate.
- 4See your result and compare against common resolutions at that ratio.
Common Use Cases
- Resize images to exact social media dimensions
- Find the correct height for a YouTube thumbnail at any width
- Check if existing image dimensions match a standard ratio
Pro Tips
- TikTok and Reels use 9:16 — that's 1080×1920px at 1080p.
- Use 'Find Ratio' to check if an existing image is truly 16:9 before exporting.
- 4:5 (1080×1350) gets more feed space on Instagram than 1:1.
Frequently Asked Questions
Aspect ratio is the proportional relationship between width and height (e.g., 16:9 means for every 16 units wide, the image is 9 units tall).
Use 'Calculate Dimension' mode, select 'Calculate Height', enter your width, choose a ratio, and click Calculate.
1080×1920 is a 9:16 aspect ratio — used by TikTok, Instagram Reels, and vertical videos.
Common 16:9 resolutions: 3840×2160 (4K), 1920×1080 (1080p), 1280×720 (720p).
Yes, completely free with no signup.
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