Guide / 01
When to use it
Use it to reduce a 1920×1080 video to a 1280-pixel-wide thumbnail while deriving the undistorted 720-pixel height, or to identify any image's simplest ratio.
MEDIA / 033
Aspect Ratio Calculator
Find image ratios and resize dimensions without distortion.
Private workspaceYour input stays on this device. HaloBench tools run in your browser whenever possible.
Aspect ratio16 : 9
1280 × 720proportional size
Guide / 02
Quick guide
- Enter the source width and height and read the ratio reduced by their greatest common divisor.
- Enter the desired new width and note the proportional output dimensions.
- Enable aspect locking in the image editor, apply the calculated size, and check whether its fit mode crops any edge.
Check
Validate the result
1920×1080 should reduce to 16:9, and a target width of 1280 should produce 1280×720.
Limits
Know the limits
Ratio inputs and the output height are rounded to whole pixels. The tool does not crop, pad, rotate, account for pixel density, or resize the file itself.
Reference
Input and output example
Use the same units and settings when comparing your result with this example.
- Example input
Width 1920 · height 1080 · new width 1280- Result and interpretation
Ratio 16 : 9 · proportional dimensions 1280 × 720
FAQ
Frequently asked
Why is part of the image cropped even after using the calculated dimensions?
The calculation only preserves the full-image ratio. A fill or cover mode can still crop edges to occupy a frame, so use contain or an aspect-lock option when the entire image must remain visible.
Does my data leave this device?
No. This tool is designed to process its working data in your browser. Advertising may load separately, but your tool input is never sent with it.