Scale 1920×1080 to width 1280
Input and settings
Original: width 1920 / height 1080 Target: width 1280 / height blank
Expected result
Ratio: 16:9 Size: 1,280 × 720
Aspect Ratio Calculator
Reduce width and height to a ratio and calculate a matching scaled dimension.
How to use
These are example steps; replace the values for your task.
- Enter an original width of 1920 and height of 1080.
- Enter 960 as the new width and check the height of 540.
Enter values
Result
About this tool
Width and height are reduced with their greatest common divisor, so 1920×1080 becomes 16:9. Enter one target dimension to calculate the other.
Any consistent measurement unit can be used. Decimal output is formatted for readability.
Continue this task
- Fluid Type Calculator — Alongside aspect ratios, calculate heading sizes that respond to viewport width.
Try a use case and check the result
Set a width or height and calculate the other dimension while keeping the original ratio.
Example buttons replace the inputs and settings above and calculate. Restore previous input steps back one example at a time. After trying multiple examples, repeat restore to return to your original input. This history is lost when the page closes.
Scale a portrait image to height 1000
Input and settings
Original: width 1080 / height 1920 Target: width blank / height 1000
Expected result
Ratio: 9:16 Size: 562.5 × 1,000
How to read the result
The large result is the reduced ratio; the next line gives the scaled dimensions. The portrait width of 562.5 is a calculated value. Choose a rounding policy at the destination if whole pixels are required. Leave target width blank to calculate from height.
Scope and limits
Original dimensions assume whole pixels and are rounded before reducing the ratio; zero or negative dimensions are invalid. A positive target width takes precedence over target height. This does not crop, resize or pad an image. Check whether destination rounding preserves the intended ratio.
Verification: existing aspectRatio and scaleAspect checks cover 16:9 and 9:16, scaling from either dimension, width precedence when both targets are entered, and rejection of zero dimensions.
Continue with the next task
Find the height at half the width
With an original size of 1920 × 1080 and a new width of 960, the new height is 540.
The original width divided by height gives the ratio. New height is new width divided by that ratio.
If both target dimensions are entered, width takes priority. Original dimensions are rounded to integers before calculating the ratio.
Frequently asked questions
What ratio is 1920×1080?
It is 16:9.
Does it work for portrait sizes?
Yes. 1080×1920 reduces to 9:16.
Does it resize an image file?
No. It calculates dimensions only.
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