RandoziImage Aspect Ratio Calculator
Type the width and height of an image to reduce them to a ratio such as 16:9. Or give a ratio and one side to get the other, or a target ratio to see how many pixels to remove on each side when you crop. A table of the usual ratios shows the height for any width.
Aspect ratio
16:9
Common ratios
| Ratio | Height | Often used for |
|---|---|---|
| 1:11 : 1 | 1200 px | Square posts, profile pictures |
| 5:41.25 : 1 | 960 px | Some large-format prints |
| 4:31.333 : 1 | 900 px | Older screens, many compact cameras |
| 3:21.5 : 1 | 800 px | 35 mm film, many cameras |
| 16:101.6 : 1 | 750 px | Many laptop screens |
| 16:91.778 : 1 | 675 px | HD video, most screens |
| 1.91:11.91 : 1 | 628 px | Link preview images |
| 2:12 : 1 | 600 px | Wide banners, panoramas |
| 21:92.333 : 1 | 514 px | Ultrawide screens, cinema-style video |
| 4:50.8 : 1 | 1500 px | Portrait posts |
| 3:40.75 : 1 | 1600 px | Portrait photos |
| 2:30.6667 : 1 | 1800 px | Portrait prints, posters |
| 9:160.5625 : 1 | 2133 px | Vertical video, stories |
Simplify: both sides divided by their greatest common divisor. Missing side: width = height × a ÷ b, height = width × b ÷ a, rounded to the nearest pixel. Crop: keeps the most pixels, rounded down to whole pixels. The page works on the numbers you type only; it does not open or change any image file, and nothing you type leaves your browser.
How it works
- Choose Simplify a ratio, Find the missing size or Crop to a ratio.
- Enter the width and height of your image, or a ratio and one known side. Click a common ratio in the table to use it.
- Read the ratio, the missing side, or the size after the crop and the pixels to remove on each side.
- Copy the summary, or use the table of common ratios to see their heights at the width you need.
What people use it for
Naming the ratio of a photo or a video
Turn 3840 × 2160 or 1080 × 1350 into the short ratio that a platform or a printer asks for.
Resizing without stretching
Find the height that keeps the ratio when a layout fixes the width at 1200 px.
Cropping a photo for a given format
See how many pixels to cut from the sides or the top and bottom to turn a 3:2 photo into 16:9 or 1:1.
Questions
- How is a ratio simplified?
- Both sides are divided by their greatest common divisor. For 1920 × 1080 the divisor is 120, which gives 16:9. Some sizes only reduce to an awkward pair, as 1366 × 768 gives 683:384; the page then shows the closest usual ratio if one is within 2 %.
- How is the missing side calculated?
- For a ratio a:b, width = height × a ÷ b and height = width × b ÷ a. A width of 1920 at 16:9 gives 1920 × 9 ÷ 16 = 1080. Pixels are whole numbers, so the result is rounded to the nearest pixel, and the page shows the exact value when it is not a whole number.
- How does the crop work?
- The crop keeps as many pixels as possible. If the image is wider than the target ratio, the width is cut to height × a ÷ b. If it is taller, the height is cut to width × b ÷ a. The size is rounded down to a whole pixel, so it never goes beyond the original, and the result shows the ratio actually reached. An odd number of pixels cannot be split in two equal halves, so one side loses one pixel more.
- Does the page open or resize my image files?
- No. It only works on the numbers you type: it does not read, upload or change any image, and nothing you type leaves your browser.