About AspectRatioCal
AspectRatioCal is a free online tool for calculating, converting, and simplifying aspect ratios. It is built for people who work with dimensions every day — video editors, photographers, UI and web designers, and developers — who need the correct proportions quickly and without doing the math by hand.
Aspect ratios are a fundamental concept in photography, video, design, and display technology. AspectRatioCal provides a clear, dependable reference for converting dimensions, comparing ratios, and finding the right resolution for any format, without unnecessary complexity.
What you can do here
- Calculate an aspect ratio from any width and height using the Aspect Ratio Calculator.
- Convert pixel dimensions while preserving a fixed ratio, in either direction.
- Simplify a resolution to its smallest whole-number ratio (for example, 1920×1080 → 16:9).
- Browse common formats in the Aspect Ratio Chart, with decimal values and example resolutions.
- Look up exact dimensions per platform in the Social Media Image Sizes guide.
How the calculator works
To simplify a ratio, the calculator divides the width and height by their greatest common divisor (GCD) — the same method used to reduce a fraction to its simplest form. That is how 1920×1080 becomes 16:9 and 1280×1024 becomes 5:4.
Calculations use exact decimal arithmetic rather than ordinary floating-point math, so ratios that include decimals — like 2.39:1 — stay precise instead of drifting to values such as 2.3900000001. When you enter a pixel dimension, the tool solves for the matching side while keeping the same proportion, with optional rounding to whole pixels.
Accuracy and reliability
Every result follows established proportional-scaling and greatest-common-divisor methods, with consistent, predictable rounding behavior so the output never misleads. AspectRatioCal is designed to be trustworthy for a quick one-off check and for repeated professional use alike.
Your data stays in your browser
All calculations run entirely on your device. The values you enter — ratios, pixel sizes, or anything else — are processed locally in your browser and are never sent to a server. You can read more in our Privacy Policy.
Who it is for
- Video creators & editors matching footage to 16:9, 9:16, or cinematic ratios.
- Photographers working across 3:2, 4:3, and 1:1 formats.
- UI, web, and graphic designers sizing images, banners, and layouts.
- Developers who need exact dimensions for responsive media and thumbnails.
Feedback
Suggestions, questions, or issue reports are welcome through the Contact page. Information about data handling is available in the Privacy Policy.