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Compress an image to between 20 KB and 50 KB
For a 20–50 KB requirement, aim for 20,480 to 50,000 bytes: that window passes whether the form counts 1 KB as 1000 or 1024 bytes. At quality 75 a 4:3 photo lands inside it from about 321 × 240 up to 510 × 382 pixels.
20–50 KB
JPG · 20-50 KB (20,480-50,000 bytes) · original pixel size · white background
PixelFit aims between 20,480 and 50,000 bytes, so the file passes whether the form counts 1 KB as 1,000 or 1,024 bytes.
Fit, background and padding white background · padding off
Saving presets is part of Pro.
The result appears here: the exact byte count, pixel size and quality, the size before and after, a preview and a download button.
The batch kit (one ZIP for up to 500 photos, several photos merged into one PDF) is part of Pro.
The safe byte window for 20–50 KB
"At least 20 KB" is 20,000 or 20,480 bytes, so the safe minimum is 20,480. "At most 50 KB" is 50,000 or 51,200 bytes, so the safe maximum is 50,000. The window is 29,520 bytes wide, 59 % of the maximum: wide enough that, at quality 75, the largest 4:3 photo inside it has 2.5 times the pixels of the smallest.
If the best result under 50,000 bytes is below 20,480, PixelFit raises quality, then pads the file only if you opt in (below).
Pixel sizes that land between 20 KB and 50 KB
At quality 75, each kind of image lands in the 20–50 KB window from the first size up to the second.
| Image | Reaches 20 KB at | Stays under 50 KB up to |
|---|---|---|
| Head-and-shoulders portrait | 309 × 385 | 562 × 701 |
| Outdoor landscape (12 MP phone photo) | 321 × 240 | 510 × 382 |
| Scanned typed document page | 304 × 382 | 485 × 609 |
| Handwritten letter with signature | 539 × 443 | 906 × 744 |
| Flat-colour graphic (flag) | 785 × 549 | 1,601 × 1,120 |
Fixed pixel sizes against 20–50 KB
When the form fixes the pixels, the file lands in the 20,480–50,000 byte window between these two JPEG qualities; "pad" means even quality 95 stays under 20 KB.
| Pixel size | Lowest quality reaching 20 KB | Highest quality under 50 KB |
|---|---|---|
| 140 × 60 (small signature box) | none: pad 17,698 bytes | 95+ |
| 300 × 120 (signature strip) | none: pad 10,149 bytes | 95+ |
| 200 × 230 (small ID photo) | 94 | 95+ |
| 413 × 531 (35 × 45 mm at 300 DPI) | 45 | 88 |
| 600 × 600 (2 × 2 inch at 300 DPI) | any (30 reaches it) | 77 |
What falls below 20 KB
Even at quality 95, the highest quality we measured (the tool also tries 100), a 4:3 photo stays under 20,480 bytes up to about 212 × 159 pixels (17 % of the pixels that still fit under 50 KB at quality 75); a handwritten page up to 305 × 250 and a portrait up to 181 × 226. From there to 321 × 240 a photo reaches 20 KB only above quality 75, and from 321 × 240 to 510 × 382 quality 75 lands inside 20–50 KB.
A 300 × 120 image (signature strip) is about 10.1 KB at quality 95, so 50 % of a 20,480-byte file would be padding; a 140 × 60 image (small signature box) is about 2.7 KB at quality 95, so 86 % of a 20,480-byte file would be padding. Padding satisfies a file-size check of 20–50 KB and leaves the pixels unchanged; where the form does not fix the pixel size, a larger image is the cleaner way to reach 20 KB.
Upload sizes against 20–50 KB at quality 75
413 × 531 (about 31.2 KB), 600 × 600 (about 45.5 KB) land inside 20–50 KB as is. Below 20 KB: 300 × 120 (3.8 KB), which needs padding; 200 × 230 (10.2 KB), which reaches it from quality 94. Just above 50 KB: 800 × 600 (about 124,200 bytes), 1080 × 1080 (about 307,000 bytes), which need a lower quality or fewer pixels.
Inside 20–50 KB at quality 75, a handwritten page runs from 539 × 443 to 906 × 744 pixels and a portrait from 309 × 385 to 562 × 701.
How to compress an image to 20–50 KB
-
Open the tool above
Preset: minimum 20 KB, maximum 50 KB, JPG.
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Add the image
Drop, paste or pick it; the 20,480–50,000 byte window is applied for you.
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Fix pixels only if required
With pixels fixed, only quality moves (and padding, if you allow it, to reach 20 KB).
-
Download
name-50kb.jpg; compare its byte count with 20–50 KB.
Forms that ask for 20–50 KB
Upload specs in our dataset with exactly this window. Verify with the official notice before you submit.
Sources
- Measured by PixelFit with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026.
- Sample images, Wikimedia Commons, checked 31 October 2026: landscape (CC0 1.0) commons.wikimedia.org/w/index.php?curid=154070378; portrait commons.wikimedia.org/w/index.php?curid=23956389; typed page commons.wikimedia.org/w/index.php?curid=194775753; handwritten letter commons.wikimedia.org/w/index.php?curid=90423615; flag commons.wikimedia.org/w/index.php?curid=361734 (public domain).
- Binary prefixes, NIST, checked 31 October 2026: physics.nist.gov/cuu/Units/binary.html
Frequently asked questions
How do I compress an image to between 20 KB and 50 KB?
Use the tool on this page, preset to 20–50 KB: it returns a JPG of 20,480 to 50,000 bytes. A 4:3 photo stays under 50 KB up to about 510 × 382 at quality 75.
What if my image comes out smaller than 20 KB?
PixelFit raises the quality first, up to 100. A 300 × 120 image (signature strip) is still only about 10.1 KB at quality 95, 10,149 bytes short of 20–50 KB, so it needs padding: opt in, and a JPEG comment segment adds the missing bytes without touching the picture.
Is a 34.4 KB file inside 20–50 KB?
Yes: anything from 20,480 to 50,000 bytes passes under both KB definitions. Exactly 51,200 bytes passes only where 1 KB = 1024 bytes.
Which pixel size lands between 20 KB and 50 KB?
At quality 75: a photo from about 321 × 240 to 510 × 382, a portrait from 309 × 385 to 562 × 701.
Related
Single limits
- Compress to 16 KB
- Compress to 20 KB Maximum only
- Compress to 25 KB
- Compress to 45 KB
- Compress to 50 KB Maximum only
- Compress to 60 KB
Ranges sharing a limit
Pixel sizes under 50 KB
- 600×315 link preview image about 47.3 KB as a quality-75 JPG
- 300×600 banner about 45.1 KB as a quality-75 JPG
- 35×35 mm photo about 42.7 KB as a quality-75 JPG