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Resize an image without stretching it

Set a pixel width, keep the original aspect ratio and check the exported dimensions.

Wuben Image Tools · Updated 2026-10-04

Resizing should make an image fit a space without making faces wider or circles oval. The important relationship is the aspect ratio: the width divided by the height. Keep that relationship when you want the whole image to retain its shape.

Use pixels for a web image

For a website or a form that asks for a width and height, start with the required pixel dimensions. A request for a physical print size or DPI is a separate requirement; this tool does not guarantee print metadata.

Resize step by step

  1. Open the image resizer and select your image.
  2. Leave Keep original proportions checked.
  3. Enter your desired width. The height updates using the original ratio.
  4. Click Process image. Check the output dimensions below the download button.
  5. Download the PNG, open it in your destination app and keep the original.

A concrete example

Our built-in sample is 640 × 400 pixels. With proportions locked, changing its width to 320 sets the height to 200. The ratio stays 1.6 in both cases. If you enter 320 × 320 with the lock disabled, the artwork is stretched into a square.

A 640 by 400 original sample image
Try this sample in the resizer, then reduce the width to 320 pixels.

What if the required shape is different?

A square requirement and a wide original cannot both be satisfied by proportional resizing alone. You need to crop part of the picture or add padding around it. Use the advanced editor for that choice instead of stretching the image.

Dimensions and file size are different

Pixel dimensions describe the image grid. KB and MB describe the encoded file. Reducing dimensions often reduces file size, but the format and image detail also matter. This resizer exports PNG, so a small original JPEG can produce a larger file even after resizing. If a service requires a JPEG under a size limit, use the compressor after resizing and verify the actual output size.

Enlarging an image does not recover lost detail. Save the original and avoid repeated lossy conversions when you can.

The quick resizer accepts still PNG, JPEG and WebP files up to 25 MB and 24 million pixels. Output dimensions must be whole numbers from 1 to 8192, with at most 24 million pixels in total.