Aspect Ratio Calculator
Enter any width and height to get the simplified ratio — then scale to a new size while keeping perfect proportions.
Aspect ratio
16:9
Scale to a new size
Enter either a new width or a new height — the other dimension is calculated automatically to preserve the ratio.
Scaled dimensions
How to use the aspect ratio calculator
- Enter the original width and height in pixels — the simplified ratio appears instantly.
- To resize, type either a new width or a new height.
- The missing dimension is calculated so proportions stay exact — no stretching.
- Use the result when exporting, cropping, or embedding images and video.
Ratios that keep images sharp
Aspect ratio is the proportional relationship between width and height, and getting it wrong is how images end up stretched, squished, or awkwardly cropped. The good news: almost every screen and platform standardizes on a handful of ratios — 16:9 for video and most displays, 4:3 for older content, 1:1 for profile pictures and Instagram posts, 9:16 for vertical video, 3:2 for many cameras. When you resize, always scale both dimensions by the same factor; changing only one dimension distorts the image. This calculator reduces any dimensions to their simplest ratio (1920×1080 becomes the familiar 16:9) and then does the scaling math for you — enter a target width for a hero image and get the exact matching height, or vice versa. It is pure math, so use it for video timelines, CSS layouts, print sizing, and social media exports alike.
Frequently asked questions
What is an aspect ratio?
The proportional relationship between an image's width and height, written like 16:9. It describes shape, not size — a phone screen and a cinema screen can share the same ratio.
What are the most common ratios?
16:9 (video, modern displays), 9:16 (vertical video), 1:1 (square posts, avatars), 4:3 (older displays), and 3:2 (many cameras).
Will resizing change my image quality?
This tool only does the math — it does not touch your files. Downscaling keeps things crisp; upscaling beyond the original size can look soft.
What does the decimal value mean?
The ratio expressed as a single number (width divided by height). 16:9 equals 1.78 — useful when software asks for a decimal ratio.