Aspect Ratio Scaler Calculator
Calculate the missing dimension when scaling an image or video while preserving its aspect ratio. Enter the original width, original height, and new width to get the proportionally correct new height.
How to use this tool
- Enter original width, original height and new width in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your new height and the full breakdown beneath it.
Formula
New Height = Original Height x (New Width / Original Width)
How it works
Compute the scale ratio by dividing the new width by the original width, then multiply the original height by this ratio to get the new height.
Worked example
Scale 1920x1080 to width 1280
- Scale ratio: 1280 / 1920 = 0.6667
- New height: 1080 x 0.6667 = 720 px
Common mistakes to avoid
- Swapping width and height inputs, which stretches the image along the wrong axis and distorts the result.
- Rounding the new height to a whole number without checking whether the video codec or platform requires even-number dimensions.
- Using this tool when the target platform enforces a fixed aspect ratio different from the source; you must crop, not just scale, to match.
Key terms
Frequently asked questions
- Can I solve for the new width given a target height instead?
- Rearrange the formula: New Width = Original Width x (New Height / Original Height). The same proportional logic applies in either direction.
- Why does my scaled video look blurry?
- Blurriness is caused by upscaling beyond the source resolution, not by the aspect ratio calculation itself. The formula preserves proportions but cannot add pixel detail that does not exist.
- What aspect ratio should I use for YouTube vs Instagram?
- YouTube prefers 16:9 (1920x1080 or 1280x720). Instagram feed is 1:1 square or 4:5 portrait. Enter your original dimensions and the target width for each platform to get the correctly scaled height.