Aspect Ratio Calculator
Aspect Ratio Calculator: free, instant and private. Enter either dimension to get the matching one without distortion.
How the Aspect Ratio Calculator works
The Aspect Ratio Calculator takes Original width (px), Original height (px), New width (blank = keep), New height (blank = keep) and returns the answer instantly — no button to hunt for, no page reload. Enter either dimension to get the matching one without distortion. This is the standard way to resize video, thumbnails and photos so nothing stretches.
Enter your own numbers to replace the example values; the result panel updates as you type. Everything runs in this single page, so nothing you enter leaves your device.
Formula used
ratio = width ÷ height, reduced by their greatest common divisor
| Symbol | Meaning |
|---|---|
| width, height | original dimensions in pixels |
| new width / new height | leave one blank to scale the other proportionally |
Enter either dimension to get the matching one without distortion. This is the standard way to resize video, thumbnails and photos so nothing stretches.
Inputs used: Original width (px), Original height (px), New width (blank = keep), New height (blank = keep).
Worked example
Take the default example — original width (px) of 1920, original height (px) of 1080, new width (blank = keep) of 1280:
- Aspect ratio: 16:9
- New width (px): 1,280
- New height (px): 720
Frequently asked questions
- What formula does the Aspect Ratio Calculator use?
- It uses ratio = width ÷ height, reduced by their greatest common divisor, where width, height is the original dimensions in pixels; new width / new height is the leave one blank to scale the other proportionally.
- Is the Aspect Ratio Calculator free?
- Yes. There is no signup, no usage limit and no watermark — the calculator runs entirely in your browser.
- How do I read the result?
- Enter either dimension to get the matching one without distortion. This is the standard way to resize video, thumbnails and photos so nothing stretches.
- Does the Aspect Ratio Calculator store or send my data?
- No. Every calculation happens locally in the page, so the numbers you type are never uploaded or logged.
- Does it work on a phone and offline?
- Yes — the page is a single lightweight file that adapts to any screen size. Once it has loaded it keeps working without a network connection.