Aspect Ratio Calculator
Scale width and height while keeping the aspect ratio, and identify the ratio itself.
Processing: This tool runs entirely in your browser. Your input and any file you open stay on your device — nothing is uploaded to a server.
How to use the aspect ratio calculator
- Fill in the fields — they start with a worked example.
- Read the answer, and the arithmetic shown beneath it.
- Copy the results, or adjust the inputs to compare scenarios.
About this tool
Give the original width and height plus one new dimension, and the other follows from the ratio. This is the arithmetic behind not squashing a picture.
The ratio is also simplified using the greatest common divisor, so 1920×1080 is identified as 16:9 rather than left as a pair of numbers. Where a size is close to a standard ratio but not exact, that is worth knowing before it gets cropped by a platform that expects one.
Common uses
- Resizing an image without distorting it.
- Finding the height for a given width at 16:9.
- Checking what ratio an existing size actually is.
Frequently asked questions
- What is 16:9 at 1200 pixels wide?
- 675 pixels tall. The ratio 16:9 means height is width × 9 ÷ 16.
- Why is my ratio an odd pair of numbers?
- Because the size is not a standard ratio. The simplified form is exact; the nearest common ratio is shown so you can decide whether to adjust.
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