How do I calculate the aspect ratio?

If you divide the width and height by the same number, the proportions are maintained. The greatest common divisor of 1920 and 1080 is 120, so dividing them by 120 is 16:9. 1200×900 is 4:3, 1080×1080 is 1:1. A vertical image 1080×1920 is 9:16, and if you change the order of width and height, the ratio will also be reversed.

File size and aspect ratio are different pieces of information. Even with the same 16:9 ratio, storage capacity varies depending on resolution, file format, compression settings, and picture complexity. You can't estimate how many kilobytes it will be just by calculating the ratio.

Procedure for finding the height appropriate for the new width

  1. Check the original width and height in the file information.
  2. Enter both values in the aspect ratio calculator. If the original is a vertical photo, add a smaller value to the width.
  3. Enter the new desired width and press Calculate.
  4. Check the new height and integer pixel results and apply them to the editing tool.
newHeight = newWidth × originalHeight / originalWidth
1280 × 1080 / 1920 = 720
1000 × 1080 / 1920 = 562.5

The first result is 1280×720, which is exactly the same 16:9 as the original. The second has an exact height of 562.5, so the tool's integer rounding value is 563. If you need the integer sizes to be exactly the same ratio, try picking a width that is a multiple of 16. For example, 992×558 is exactly 16:9.

Difference between maintaining ratio, cropping, and adding margin

Reducing the width and height to the same scale maintains the overall scene and proportions. To fit a 16:9 photo into a square box without any empty space, you need to crop part of it or change the ratio to enlarge it. Stretching changes the shape of your subject, so you may want to consider adding some space to preserve the entire scene. This calculator does not include cropping or adding margins.

The Moyoutil image resizing tool calculates the height to fit the original proportions based on the width. Since video output may have separate size conditions allowed by the encoder, not all programs accept the calculated value as is. If the calculation is small enough to be rounded to 0 pixels, increase the new width. Also, calculating larger than the original does not restore details that were not present.

The ratio and pixel examples in this article are verified with actual function results from a calculator. Upload specifications for specific platforms may change, so please check separately the current specifications for the service you wish to post to.

Frequently Asked Questions

Do I need to upload an image?

No. Just enter the numbers for Original Width, Original Height, and New Width. This tool does not read image content or save files.

Is it possible to calculate the width based on the new height?

The current screen is based on the new width. If you need to calculate based on height, change the input order of the original width and height and put the desired height in the new width field. The resulting height value corresponds to the new width in the original orientation.