Enter a width and height to see the simplified aspect ratio, then type a new width or height to resize without stretching.
How it works
The ratio is the width divided by the height, reduced to the smallest whole numbers using the greatest common divisor. For example, 1920 by 1080 reduces to 16:9. To resize, multiply or divide by the same ratio so the picture is not stretched.
Frequently asked questions
What is the aspect ratio of 1080p and 4K?
Both 1920 by 1080 and 3840 by 2160 are 16:9.
Why do some videos have black bars?
Black bars appear when the video ratio differs from the screen ratio, for example a 21:9 film on a 16:9 screen.
Which ratio is best for a projector?
16:9 suits most content. Choose 16:10 for work screens or 21:9 if you mainly watch widescreen films.
More free projector tools
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