Formula and example
To find height, use height = width x ratio height / ratio width. For a 16:9 design that is 1920 px wide, height = 1920 x 9 / 16 = 1080 px.
Image Tools
Aspect Ratio Calculator
Calculate a missing width or height from a target aspect ratio, or simplify image and video dimensions into a clean ratio before resizing, cropping, or preparing upload-ready image assets.
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Works instantly with no signup.
Calculator
Calculate a missing width or height
Enter a ratio and one known dimension, or choose a common preset before resizing or cropping an image.
Result16:9
1920 x 1080 px
Decimal ratio: 1.7778Local processing: Your aspect ratio values are calculated in your browser. They are not uploaded to our server.
How to use this calculator
Choose the ratio you need, such as 16:9 for widescreen video, 4:3 for classic slides, or 1:1 for a square. Use a preset or enter a custom ratio, then enter either the width or the height. The missing dimension updates automatically while preserving the same shape.
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Use the result with Resize Image when you need exact final pixels, or with Crop Image when you need a square, portrait, widescreen, or profile-picture composition before export.
FAQ
What is an aspect ratio?
An aspect ratio is the proportional relationship between width and height. A 16:9 image stays the same shape at 1280 x 720, 1920 x 1080, and 3840 x 2160.
Can I calculate width from height?
Yes. Leave the width field empty, enter a height, and the calculator returns the matching width for the selected ratio.
Which ratio should I use for a profile picture?
Use 1:1 for a square or circle profile image. Calculate the final size here, then use Crop Image to frame the subject and Resize Image if you need exact pixels.
How does this help before resizing?
If you know one final dimension, the calculator gives the matching width or height so the image can be resized without stretching.
Does this upload anything?
No. This calculator only works with numbers in your browser and does not upload files or dimensions to a server.
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