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Compress an image to between 30 KB and 50 KB
For a 30–50 KB requirement, aim for 30,720 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 398 × 298 up to 510 × 382 pixels.
30–50 KB
JPG · 30-50 KB (30,720-50,000 bytes) · original pixel size · white background
PixelFit aims between 30,720 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 30–50 KB
"At least 30 KB" is 30,000 or 30,720 bytes, so the safe minimum is 30,720. "At most 50 KB" is 50,000 or 51,200 bytes, so the safe maximum is 50,000. The window is 19,280 bytes wide, 39 % of the maximum: narrow enough that a fixed pixel size has only a short band of qualities landing inside.
If the best result under 50,000 bytes is below 30,720, PixelFit raises quality, then pads the file only if you opt in (below).
Pixel sizes that land between 30 KB and 50 KB
At quality 75, each kind of image lands in the 30–50 KB window from the first size up to the second.
| Image | Reaches 30 KB at | Stays under 50 KB up to |
|---|---|---|
| Head-and-shoulders portrait | 408 × 509 | 562 × 701 |
| Outdoor landscape (12 MP phone photo) | 398 × 298 | 510 × 382 |
| Scanned typed document page | 374 × 469 | 485 × 609 |
| Handwritten letter with signature | 686 × 563 | 906 × 744 |
| Flat-colour graphic (flag) | 1,087 × 760 | 1,601 × 1,120 |
Fixed pixel sizes against 30–50 KB
When the form fixes the pixels, the file lands in the 30,720–50,000 byte window between these two JPEG qualities; "pad" means even quality 95 stays under 30 KB.
| Pixel size | Lowest quality reaching 30 KB | Highest quality under 50 KB |
|---|---|---|
| 140 × 60 (small signature box) | none: pad 27,938 bytes | 95+ |
| 300 × 120 (signature strip) | none: pad 20,389 bytes | 95+ |
| 200 × 230 (small ID photo) | none: pad 8,297 bytes | 95+ |
| 413 × 531 (35 × 45 mm at 300 DPI) | 73 | 88 |
| 600 × 600 (2 × 2 inch at 300 DPI) | 48 | 77 |
What falls below 30 KB
Even at quality 95, the highest quality we measured (the tool also tries 100), a 4:3 photo stays under 30,720 bytes up to about 262 × 196 pixels (26 % of the pixels that still fit under 50 KB at quality 75); a handwritten page up to 377 × 309 and a portrait up to 236 × 294. From there to 398 × 298 a photo reaches 30 KB only above quality 75, and from 398 × 298 to 510 × 382 quality 75 lands inside 30–50 KB.
A 200 × 230 image (small ID photo) is about 21.9 KB at quality 95, so 27 % of a 30,720-byte file would be padding; a 140 × 60 image (small signature box) is about 2.7 KB at quality 95, so 91 % of a 30,720-byte file would be padding. Padding satisfies a file-size check of 30–50 KB and leaves the pixels unchanged; where the form does not fix the pixel size, a larger image is the cleaner way to reach 30 KB.
Upload sizes against 30–50 KB at quality 75
413 × 531 (about 31.2 KB), 600 × 600 (about 45.5 KB) land inside 30–50 KB as is. Below 30 KB: 300 × 120 (3.8 KB), which needs padding; 200 × 230 (10.2 KB), which needs padding. 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 30–50 KB at quality 75, a handwritten page runs from 686 × 563 to 906 × 744 pixels and a portrait from 408 × 509 to 562 × 701.
How to compress an image to 30–50 KB
-
Open the tool above
Preset: minimum 30 KB, maximum 50 KB, JPG.
-
Add the image
Drop, paste or pick it; the 30,720–50,000 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 30 KB).
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Download
name-50kb.jpg; compare its byte count with 30–50 KB.
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 30 KB and 50 KB?
Use the tool on this page, preset to 30–50 KB: it returns a JPG of 30,720 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 30 KB?
PixelFit raises the quality first, up to 100. A 200 × 230 image (small ID photo) is still only about 21.9 KB at quality 95, 8,297 bytes short of 30–50 KB, so it needs padding: opt in, and a JPEG comment segment adds the missing bytes without touching the picture.
Is a 39.4 KB file inside 30–50 KB?
Yes: anything from 30,720 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 30 KB and 50 KB?
At quality 75: a photo from about 398 × 298 to 510 × 382, a portrait from 408 × 509 to 562 × 701.
Related
Single limits
- Compress to 25 KB
- Compress to 30 KB Maximum only
- Compress to 35 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