Aspect Ratio Calculator
Calculate aspect ratios, simplify dimensions, and resize images or videos proportionally. Free online 16:9, 4:3, and custom ratio calculator.
Resize proportionally
Aspect ratio
16:9
Landscape • decimal ratio 1.7778 • nearest common ratio 16:9
Target height for 1200px width
675px
Target width for 630px height
1120px
CSS helpers
aspect-ratio: 16 / 9;
padding-top: 56.25%;
How to Use This Aspect Ratio Calculator
- Enter the original width and height.
- Review the simplified aspect ratio and decimal ratio.
- Type a target width or target height to resize proportionally.
- Use the CSS helpers if you are building responsive layouts or embeds.
What An Aspect Ratio Calculator Does
An Aspect Ratio Calculator simplifies dimensions like 1920 by 1080 into a clean ratio such as 16:9. It also helps you resize images, videos, thumbnails, and layout boxes without distortion by calculating the matching width or height automatically.
Where Aspect Ratios Matter
- YouTube thumbnails, shorts, and video exports
- Instagram, TikTok, and other social media creatives
- Website images, hero banners, and embedded media
- Print layouts, slide decks, and product mockups
Useful Output From This Tool
- Simplified ratio such as 1:1, 4:3, 3:2, 16:9, or 9:16
- Nearest common ratio for fast comparison
- Calculated width or height for proportional resizing
- CSS aspect-ratio and padding-top values for responsive design
Frequently Asked Questions
How do I keep an image from stretching when resizing it?
Resize proportionally using the same aspect ratio. This tool calculates the matching width or height automatically so the image does not distort.
What is the aspect ratio of 1920x1080?
1920x1080 simplifies to 16:9, which is the most common widescreen video ratio.
Can I use this for video as well as images?
Yes. Aspect ratios apply equally to images, video frames, embeds, slides, and other visual layouts.