Every ratio,
every screen

Divide width by height, then simplify both numbers by their greatest common divisor to get the smallest whole-number ratio, such as 1920×1080 simplifying to 16:9.

No. Aspect ratio is a proportion, so it stays the same regardless of unit, as long as width and height use the same unit.

Use the Dimension Converter: enter your current width and height, then type a new width or height — the other value is calculated automatically to preserve the exact same ratio.

Pixel density is how many pixels are packed into each inch of a screen. Higher PPI generally means a sharper image at normal viewing distance; it's calculated from resolution and diagonal screen size.

Letterboxing adds bars above and below video to fit a wider source into a narrower frame. Pillarboxing adds bars on the sides to fit a narrower source into a wider frame. Both preserve the original ratio without stretching.

No. Images you upload for the preview stay entirely in your browser session and are never uploaded to a server.

Some resolutions are close to but not exactly a common ratio (for example 1366×768 is close to 16:9 but not exact), so the tool also shows the nearest standard ratio for reference.

Resolution is the exact pixel count of width and height (e.g. 1920×1080). Aspect ratio is the simplified proportion between them (e.g. 16:9). Many resolutions can share the same ratio.