How to compress a JPG to 100KB
- Select Choose files, or drop a JPG photo on the box.
- The tool aims for under 100KB, which is 102,400 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 100KB limit comes from
The 100KB mark is probably the most common JPG limit: many online application forms, portals and content systems ask for a JPG under 100KB. It keeps a standard photo clear while holding storage down.
What 100KB means in pixels
100KB is 102,400 bytes, or 819,200 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 100KB.
| Picture size | Pixels | Bits per pixel | At 100KB |
|---|---|---|---|
| 640×480 | 307,200 | 2.67 | comfortable, the tool keeps all pixels |
| 1024×768 | 786,432 | 1.04 | fine for photos |
| 1600×1200 | 1,920,000 | 0.43 | too tight, the tool shrinks the picture |
| 4000×3000 | 12,000,000 | 0.07 | too tight, the tool shrinks the picture |
At 1.5 bits per pixel, 100KB holds a picture of about 853×640 pixels in a 4:3 shape (545,920 pixels). A JPG of about 1000 pixels wide fits in 100KB at 70 to 85 percent quality. A raw phone photo is reduced in pixels and quality until it fits. You can see the final dimensions in the result row.
About the output format
The output is always a JPG, so JPG-only fields accept it. If your source is a PNG, use the PNG to 100KB page, which explains that PNG input comes out as WebP.
Tips
- If a form demands both a size and a pixel size, resize first with the image resizer.
- Do not rename a PNG to .jpg. Convert it properly with PNG to JPG.
- For a bit more headroom see the general 100KB page, which also accepts WebP.
- See also: compress JPG to 50KB, compress to 100KB, compress PNG to 100KB, image compressor.
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