Aspect Ratio Calculator
Give it one side and it tells you the other side that keeps the ratio.
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GIVE ONE SIDE, TAKE THE OTHER.
The Aspect Ratio Calculator takes a ratio and one known side and works out the other side. Among the ready ratios are 16:9 landscape video, 9:16 portrait video and stories, 1:1 square, 4:5 portrait post, 4:3 classic screen, 3:2 camera, 21:9 ultrawide and 2.39:1 cinema; for a ratio not on the list you can write the width and height yourself. You give the width and find the height, or give the height and find the width.
The result shows the width and height in pixels, the decimal value of the ratio, its simplified form (16:9 for 1920 × 1080) and the total number of pixels. Because most video encoders want even numbers, the size rounded to an even number is given separately as well. If rounding to a whole number shifted the ratio very slightly, that difference is written as a percentage. It is used to find the right size before resizing a video, designing a cover or working out an image area. The calculation is done entirely in your browser.
From start to finish
- Choose the ratio. Pick one of the ready ratios or write the width and height with “Custom ratio”.
- Enter the known side. Choose whether you know the width or the height and write the value in pixels.
- Read the result. The other side, the simplified ratio and the size rounded to an even number appear instantly.
Frequently asked questions
How many pixels of height does 9:16 make at a width of 1920?
3413.33 pixels; rounded to a whole number 3413, rounded to an even number 3414. The common portrait video size, though, is 1080 × 1920.
Why an even number?
Because many video encoders store the color information in blocks of two pixels, they do not accept odd sizes or they crop one pixel. An even number avoids that problem.
How do I find the ratio of a size I do not know the ratio of?
Write the size itself into the “Custom ratio” fields (1280 and 1024, for example); the simplified ratio in the result appears as 5:4.
Is the data I enter sent to the server?
No. This tool runs entirely in your browser; nothing you type or add is sent to the RUPO Studio server. It keeps working while the page is open even if your internet connection drops. No account needed. It is free to use: there is no hourly or daily limit, and we don't make you watch an ad before you see the result.
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