What this tool does
The Aspect Ratio Calculator turns any pair of dimensions into a clean, simplified ratio such as 16:9 or 4:3. It is handy for designers checking image proportions, video editors matching footage to a frame, web developers sizing containers, and anyone who needs to resize without distortion. Instead of doing the math by hand, you get the answer instantly.
How to use it
- Enter the Width of your image, screen, or design in pixels or any unit.
- Enter the Height in the same unit.
- (Optional) Type a New width if you want to scale to a different size.
- Select Calculate to see the simplified ratio, the decimal ratio, and the matching height for your New width.
A quick worked example
Say you have a photo that is 1920 by 1080. Set Width to 1920 and Height to 1080, and the tool reports a 16:9 ratio with a decimal of about 1.78. Now suppose you need it to fit a 1280 pixel wide column. Put 1280 in New width and the calculator returns a height of 720, keeping the picture in perfect proportion with no stretching or cropping.
Everything runs right in your browser, so your numbers never leave your device. The tool is private, completely free, and needs no sign-up.
Frequently asked questions
- What aspect ratio is 1920x1080?
- A resolution of 1920 by 1080 simplifies to a 16:9 aspect ratio, which is the standard for most monitors, TVs, and online video.
- How do I resize an image without stretching it?
- Enter the original width and height, then type the new width you want. The calculator returns the matching height that keeps the exact same proportions, so nothing looks squished.
- What does the decimal ratio mean?
- The decimal ratio is the width divided by the height. For example, 16:9 equals about 1.78, which is a quick way to compare two ratios at a glance.
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Last updated: June 17, 2026