How to use
01
Enter width and height to get the reduced ratio.
02
Enter a ratio or choose a preset, then provide the known width or height.
Exact aspect ratio
The exact aspect ratio shows the relationship between the width and height you entered, reduced to its simplest form.
Closest common ratio
If your dimensions are close to a familiar format such as 16:9 or 4:3, the calculator may show that format as a reference. It does not replace the exact ratio.
Rounded dimensions
A missing-dimension calculation can produce a decimal. When you need whole-number dimensions, the calculator also shows the nearest whole-number result. Rounding slightly changes the mathematical ratio.
16:9
TVs, monitors, online video
A common widescreen format; it does not indicate image quality
4:3
Older displays and legacy video
Can produce side bars on widescreen displays
16:10
Productivity monitors and some laptops
Slightly taller than 16:9
21:9
Actual device and content ratios can vary
32:9
Super-ultrawide monitors
About as wide as two 16:9 displays side by side
9:16
Vertical video and phone-first layouts
Vertical video and mobile layouts
1:1
Square images and layouts
Width and height are equal
When the source device and destination screen use different aspect ratios, mirrored content may show black bars, crop at the edges, or be fitted differently to the display.
Matching aspect ratios does not mean the devices have the same resolution or image quality. The mirroring method, receiver capabilities, app behavior, and display settings can also affect how the image appears.
Dimensions may be rounded, cropped, scaled, or created for a non-standard size. When your result is sufficiently close to a common format, the calculator may show that format separately while preserving your exact ratio.
Simple guides, honest app reviews, and practical fixes for screen mirroring.
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