How to compress an image to 20KB
- Select Choose files, or drop a JPG, PNG or WebP image on the box.
- The tool aims for under 20KB, which is 20,480 bytes here. It tests quality levels from 95 down to 40 percent and keeps the sharpest result that fits.
- If 40 percent is still too big, it shrinks the width and height by 15 percent at a time until the file fits.
- Select Download. The result ends in
-compressed, so your original is untouched.
Where a 20KB limit comes from
A 20KB ceiling is one of the tightest limits you will meet. Many online application forms use it for small photos and signatures, where the file only has to be recognisable on a screen, not printed.
What 20KB means in pixels
20KB is 20,480 bytes, or 163,840 bits. Divide that by the number of pixels and you get the bits each pixel can use. Photos look fine at about 1.5 bits per pixel or more, and the table shows how common sizes fare at 20KB.
| Picture size | Pixels | Bits per pixel | At 20KB |
|---|---|---|---|
| 640×480 | 307,200 | 0.53 | soft, expect some shrinking |
| 1024×768 | 786,432 | 0.21 | too tight, the tool shrinks the picture |
| 1600×1200 | 1,920,000 | 0.09 | too tight, the tool shrinks the picture |
| 4000×3000 | 12,000,000 | 0.01 | too tight, the tool shrinks the picture |
At 1.5 bits per pixel, 20KB holds a picture of about 382×287 pixels in a 4:3 shape (109,634 pixels). At this size expect a small picture. Photos with plain backgrounds, such as a face against a wall, compress well. Busy scenes with grass, text or fabric do not, and the tool will shrink the dimensions until the file fits. Check the result row for the final pixel size before you upload.
Tips
- Crop to the face or the subject first with the crop tool. Fewer pixels means a sharper picture at 20KB.
- A plain, evenly lit background compresses far better than a patterned one.
- If the form also demands exact pixels, set those with the image resizer before compressing.
- See also: compress JPG to 20KB, compress image to 30KB, compress to 50KB, image compressor.
Your images stay on your device. Nothing is uploaded, and there is no sign-up.