Aspect Ratio Calculator
Enter width or height to calculate the matching dimension for any aspect ratio. Includes presets, live preview, and resolution tables.
| 이름 | 너비 | 높이 |
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What Is an Aspect Ratio Calculator?
An aspect ratio calculator helps you find the correct width or height when you know one dimension and the desired ratio. For example, if you need a 16:9 video at 1920px wide, it tells you the height is 1080px. This is essential for video editing, responsive web design, image cropping, and display configuration.
How to Calculate Aspect Ratio
- Select a Preset — Click a common ratio like 16:9, 4:3, or 1:1, or enter custom ratio numbers
- Choose Lock Mode — Lock Width to calculate Height, or Lock Height to calculate Width
- Enter a Dimension — Type the known width or height in pixels
- Read the Result — The other dimension is calculated instantly with a visual preview
- Check Resolutions — Scroll down to see standard resolutions for the selected ratio
Why Use This Aspect Ratio Calculator?
- 9 Preset Ratios — One-click selection for the most common aspect ratios including ultrawide and portrait
- Custom Ratios — Enter any ratio numbers for specialized needs
- Bidirectional — Lock either width or height and calculate the other
- Visual Preview — See the ratio shape rendered as a proportional box in real-time
- Resolution Tables — Standard resolutions (720p, 1080p, 4K, etc.) for each ratio
- Swap Function — Quickly switch between landscape and portrait orientations
- No Server Required — All calculations happen in your browser instantly
FreeToolbox vs Other Aspect Ratio Tools
| Feature | FreeToolbox | CalculateAspectRatio.com | Andrew Hedges |
|---|---|---|---|
| Preset ratios | 9 | 4 | 3 |
| Custom ratio | Yes | Yes | Yes |
| Visual preview | Yes | No | No |
| Resolution table | Yes | No | No |
| Lock mode toggle | Yes | No | No |
| Dark mode | Yes | No | No |
| Ads | Minimal | Heavy | None |
FAQ
What is the most common aspect ratio?
16:9 is the most widely used aspect ratio for monitors, TVs, and video content. It's the standard for Full HD (1920×1080), 4K (3840×2160), and most YouTube videos.
What aspect ratio is best for social media?
It depends on the platform. Instagram posts use 1:1 (square) or 4:5 (portrait). Instagram/TikTok stories use 9:16 (vertical). YouTube thumbnails use 16:9. Twitter images work best at 16:9 or 2:1.
How do I find the aspect ratio of an image?
Divide the width by the height, then simplify. For example, 1920÷1080 = 1.778, which is 16÷9. This tool automatically simplifies ratios using GCD (Greatest Common Divisor).
What is 21:9 used for?
21:9 (ultrawide) is used for ultrawide monitors and cinematic video content. Common resolutions are 2560×1080 (UWFHD) and 3440×1440 (UWQHD).
Can I use this for print media?
Yes. While the dimensions show in pixels, you can use any unit. The ratio calculation works the same whether your values are in pixels, inches, centimeters, or millimeters.