Compress Image to KB Online (20KB, 50KB, 100KB, 200KB)

What this tool does

Add an image, set a target size in KB, and the tool shrinks the file until it fits. It’s meant for forms that cap the upload size, such as 20 KB, 50 KB, 100 KB or 200 KB. It runs in your browser, so your photo, signature or scanned document isn’t uploaded to our server.

How to use it

1. Drop your image into the upload box, or click the box to pick a file from your phone or computer. The tool accepts JPG, PNG and WebP files up to 25 MB.
2. Type your target size in KB, or tap a preset button such as 20 KB or 50 KB.
3. Choose the output format. Pick JPEG if a form asks for JPG. Pick WebP only for websites.
4. Choose a compression mode: Smart, which adjusts quality and size together, or a fixed-dimension mode.
5. Compare the original and the result. Check the file size, the pixel size and how the image looks.
6. Click Download Compressed Image to save the file.

What happens to your image

The tool first tries lower quality settings to reach your target. If the file is still too big at low quality, it reduces the width and height in proportion and tries again. A photo with fewer pixels needs less data, so this step often makes the biggest difference.

A PNG with a transparent background is filled with white when it is saved as a JPEG. Without that, JPEG would turn the transparent area black.

Read the form’s rules first

Limits differ from one exam, job portal or admission form to the next, and they change from year to year. A photo and a signature often have different limits. Read the notice or the upload page and note four things: the maximum size, the minimum size if there is one, the pixel size and the file format.

This tool changes the file size. To change the width and height in pixels or centimetres, use our photo and signature resizer.

A worked example

Say a form wants a photo of 200 by 230 pixels. That’s 46,000 pixels. Stored uncompressed at 3 bytes per pixel, it takes 138,000 bytes, about 135 KB. JPEG usually cuts a photo to roughly a tenth of that, so you can expect about 14 to 20 KB at normal quality. A 50 KB limit leaves plenty of room.

A phone photo of 4,000 by 3,000 pixels has 12,000,000 pixels, which is about 260 times more than 46,000. That’s why a phone photo can’t reach 50 KB by quality alone. It has to be made smaller in pixels too.

Limits to know

• The result usually lands a little under your target, not exactly on it. If the form has a minimum size, set your target inside the allowed range.
• Some systems count 1 KB as 1,000 bytes and others as 1,024 bytes. Aim a few KB below an upper limit to be safe.
• A very low target on a large image will look blurry. If the result looks too soft, raise the target a little or crop the photo first.
• Compressing an already compressed file loses more detail each time. Always start from the original.