How to compress an image to 30KB
- Select Choose files, or drop a JPG, PNG or WebP image on the box.
- The tool aims for under 30KB, which is 30,720 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 30KB limit comes from
A 30KB limit sits just above the smallest form caps. Profile photo fields on some portals and small thumbnails in content systems ask for this size, because it loads instantly even on a weak mobile connection.
What 30KB means in pixels
30KB is 30,720 bytes, or 245,760 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 30KB.
| Picture size | Pixels | Bits per pixel | At 30KB |
|---|---|---|---|
| 640×480 | 307,200 | 0.80 | soft, expect some shrinking |
| 1024×768 | 786,432 | 0.31 | too tight, the tool shrinks the picture |
| 1600×1200 | 1,920,000 | 0.13 | too tight, the tool shrinks the picture |
| 4000×3000 | 12,000,000 | 0.02 | too tight, the tool shrinks the picture |
At 1.5 bits per pixel, 30KB holds a picture of about 467×350 pixels in a 4:3 shape (163,450 pixels). Thirty kilobytes is enough for a clear, face-sized photo at a few hundred pixels across, but not for a full phone photo. A 12 megapixel camera shot will be scaled down a lot. Passport style pictures with a flat background usually come out clean.
Tips
- Resize to about 400 pixels on the long side first. The tool then has to cut quality far less.
- JPG files tend to reach 30KB more easily than screenshots, because photos hide compression better.
- Need smaller? Try 20KB. Need a bit more room? Try 50KB.
- See also: compress image to 20KB, compress to 50KB, compress to 100KB, passport photo size.
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