Scale any width or height while keeping the same proportions, with the simplified ratio and common format name.
How this calculator arrives at its answer
An aspect ratio is the relationship between width and height, reduced to its simplest form. 1920 by 1080 and 1280 by 720 look identical because both reduce to 16:9 — only the pixel count differs.
Enter one new dimension and the calculator solves the other, so images, video frames and layout containers scale without stretching. It also names the ratio where it matches a standard format.
Worked example
Take the starting scenario, a scale by of New width — find the height. That gives a new dimensions of 1280 × 720. Underneath, Simplified ratio comes out at 16:9 and Common name at Widescreen HD. Change any field and every figure updates as you type.
Step by step
- Enter the original width and height.
- Choose whether you are setting a new width or a new height.
- Read the matching dimension and the simplified ratio.
Formula reference
ratio = width ÷ height
new height = new width ÷ ratio · new width = new height × ratio
simplified by dividing both sides by their greatest common divisor
Common questions
What is 16:9?
The standard widescreen ratio used by almost all modern displays and video. 1920×1080, 2560×1440 and 3840×2160 are all 16:9.
How do I keep an image from stretching?
Scale both dimensions by the same factor. Setting one and letting this calculator derive the other guarantees that.
What is the difference between aspect ratio and resolution?
Resolution is the actual pixel count; aspect ratio is the shape. Many resolutions share one ratio.