Screen Aspect Ratio Calculator
Work out the simplified aspect ratio of a screen, image or video from its width and height, identify common names like 16:9 or 4:3, and scale the resolution to a new width while keeping the same proportions. Enter the pixel dimensions to see the ratio, megapixels, decimal ratio and a scaled resolution.
Formula
GCD = Greatest Common Divisor of width & height
Ratio = (width/GCD):(height/GCD)
Scaled height = new_width × (original_height / original_width)
Example: 1920 × 1080 scaled to 2560 wide
Inputs
- Width: 1920 px
- Height: 1080 px
- Scale to New Width: 2560 px
1920 and 1080 share a greatest common divisor of 120, giving a 16:9 ratio (Widescreen). That is 2.07 MP, and scaling to 2560 px wide keeps 16:9 at 2560 × 1440.
Frequently asked questions
How is the aspect ratio simplified?
The calculator divides both width and height by their greatest common divisor (GCD). For 1920 × 1080 the GCD is 120, which reduces to 16:9.
What do the common names mean?
Familiar ratios get labels: 16:9 is Widescreen, 4:3 is Standard, 21:9 is Ultrawide, 1:1 is Square, and so on. Unrecognised ratios are shown as the bare numbers.
How does scaling to a new width work?
It keeps the original proportions: new height = new width × (original height ÷ original width). So a 16:9 image scaled to 2560 px wide becomes 2560 × 1440.
What is the decimal ratio?
It is width divided by height as a single number — for example 16:9 ≈ 1.7778 — handy when a tool wants the ratio as one value.
Does it matter what units I use?
No. Aspect ratio depends only on the proportion of width to height, so pixels, centimetres or inches all give the same simplified ratio.