Image aspect ratio calculator
Calculate image aspect ratios and find proportional width and height dimensions for photos, web graphics and social media.
In your browser
Pixel dimensions (px)
CSS Snippet
Common Aspect Ratio Guide
| Aspect Ratio | Decimal | Common Uses | Standard Resolutions |
|---|---|---|---|
| 16:9 | 1.778 | YouTube, widescreen displays, TV broadcasting, desktop monitors | 1920×1080 (FHD), 3840×2160 (4K), 1280×720 (HD) |
| 9:16 | 0.563 | TikTok, Instagram Reels, YouTube Shorts, smartphone stories | 1080×1920, 720×1280 |
| 4:3 | 1.333 | Classic TV monitors, iPad screens, point-and-shoot cameras | 1024×768, 1600×1200, 2048×1536 |
| 1:1 | 1.000 | Square social media feeds (Instagram, LinkedIn), avatars, profile photos | 1080×1080, 800×800, 500×500 |
| 21:9 | 2.333 | Ultrawide gaming monitors, theatrical film releases, anamorphic video | 2560×1080, 3440×1440, 5120×2160 |
| 3:2 | 1.500 | 35mm film, DSLR & mirrorless photography, Microsoft Surface laptops | 6000×4000, 3000×2000 |
Also with the aspect ratio calculator
About this tool
Calculate matching width and height dimensions for any image or video aspect ratio. Enter one dimension to calculate the other automatically, or click any standard resolution preset.
How to use it
- 1 Choose a standard ratio preset (16:9, 9:16, 4:3, 1:1, 21:9) or type custom ratio values.
- 2 Enter either the Width or Height in pixels; the other dimension calculates automatically.
- 3 Click any common resolution button (1080p, 4K, 720p, TikTok) for instant dimensions.
- 4 Copy the CSS aspect-ratio snippet or pixel dimensions to use in your project.
Questions
How do I calculate 16:9 dimensions?
For a 16:9 ratio: Height = Width × 9 / 16 (for 1920px width, height is 1080px). Width = Height × 16 / 9.
What are the most common aspect ratios?
16:9 is the standard for widescreen monitors and YouTube; 9:16 is for TikTok and Reels; 4:3 is classic TV/iPad; and 1:1 is square Instagram feeds.
What is the formula to calculate aspect ratio?
Aspect ratio is the proportional relationship between width and height: Aspect Ratio = Width / Height. To calculate height from width: Height = Width × (Ratio Height / Ratio Width). To calculate width from height: Width = Height × (Ratio Width / Ratio Height).
What is the best aspect ratio for YouTube, TikTok and Instagram?
YouTube horizontal videos and standard desktop screens use 16:9 (1920×1080). TikTok, Instagram Reels, and YouTube Shorts use 9:16 vertical video (1080×1920). Instagram feed posts typically use 1:1 square (1080×1080) or 4:5 portrait (1080×1350).
How do I use the CSS aspect-ratio property?
Modern CSS supports the native aspect-ratio property, for example: aspect-ratio: 16 / 9; or aspect-ratio: 1 / 1;. This maintains element proportions responsively without needing older padding-bottom percentage hacks.
How do I find the aspect ratio of an existing image?
Divide the image width by the greatest common divisor (GCD) of the width and height, and do the same for the height. For example, 1920 × 1080 divided by GCD 120 yields exactly 16:9.
Is my data uploaded?
No. This tool runs in your browser, so your text and files never reach our server.
Is this tool free?
Yes. It’s free to use with no sign-up and no limits for normal use.
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