Introduction
Aspect ratio describes the proportional relationship between width and height. Images with different pixel dimensions can share the same aspect ratio.
Understanding the distinction between ratio, resolution and physical print size helps avoid stretching, unexpected cropping and low-quality output.
Key concept
Aspect ratio = width ÷ height. A 1920 × 1080 image simplifies to 16:9, and a 1280 × 720 image has the same ratio even though it contains fewer pixels.
Formula example
To preserve a 16:9 ratio at a width of 1,600 pixels, calculate height = 1,600 × 9 ÷ 16 = 900 pixels.
For print, pixel dimensions combine with pixels per inch to estimate physical size. Aspect ratio alone does not determine print sharpness.
Common mistakes
Changing width without adjusting height stretches the image. Cropping preserves the ratio but removes content near one or more edges.
A larger file size does not always mean higher resolution, because file format and compression also affect storage size.
Choosing dimensions
Start with the target platform's recommended ratio, select a sufficient pixel resolution and preview important content inside any expected crop area before exporting.