Last updated October 12, 2026 · Report an error
An aspect ratio expresses a width-to-height relationship in its simplest whole-number form — 1920×1080 and 1280×720 are both the same 16:9 ratio, just at different resolutions.
This calculator simplifies any width and height into its clean aspect ratio.
How it works
Enter a width and height. The calculator finds their greatest common divisor (GCD) and divides both numbers by it, producing the simplest whole-number ratio.
- Enter width.
- Enter height.
- Click Calculate to see your results.
Examples
1920 × 1080
A 1920×1080 resolution simplifies to a 16:9 aspect ratio, since the GCD of 1920 and 1080 is 120.
Who should use it
- Finding the aspect ratio of an image, video, or screen resolution.
- Checking whether two different resolutions share the same aspect ratio before resizing.
Industry applications
- Web design and front-end development
- Video production and photography
Advantages
- Finds the true simplest ratio using an exact GCD calculation, not a rough approximation.
- Handles decimal (non-integer) dimensions correctly.
Limitations
- Only reports the simplified ratio — doesn't suggest specific target resolutions matching that ratio.
Common mistakes to avoid
- Assuming two images with the same aspect ratio are the same size — ratio only describes proportions (shape), not actual dimensions.
- Confusing aspect ratio (width:height) with resolution (actual pixel dimensions) — many different resolutions share the same ratio.
Best practices
- When resizing an image or video to fit a new resolution while preserving its shape, first confirm the target resolution shares the same aspect ratio — otherwise the image will be stretched or need cropping.
Tips
- When cropping an image for a specific platform (like a 1:1 square for a social media profile photo), calculate the aspect ratio of your source image first to see how much you'll need to crop to fit the target ratio.
Frequently asked questions
Yes, with no signup and no limit on how many dimensions you check.
Both resolutions reduce to 16:9 when divided by their greatest common divisor — they represent the same shape (proportions) at different actual sizes, much like 1/2 and 2/4 are the same fraction.
16:9 is standard for widescreen video and most modern displays, 4:3 was standard for older TVs and monitors, 1:1 is square (common on social media), and 21:9 is used for ultrawide monitors and cinematic video.
Yes — the calculator scales decimal inputs up to whole numbers first before finding the greatest common divisor, so non-integer dimensions still simplify correctly.