Updated · how we check
Compress an image to between 20 KB and 300 KB
For a 20–300 KB requirement, aim for 20,480 to 300,000 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 1,232 × 924 pixels.
20–300 KB
JPG · 20-300 KB (20,480-300,000 bytes) · original pixel size · white background
PixelFit aims between 20,480 and 300,000 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 20–300 KB
"At least 20 KB" is 20,000 or 20,480 bytes, so the safe minimum is 20,480. "At most 300 KB" is 300,000 or 307,200 bytes, so the safe maximum is 300,000. The window is 279,520 bytes wide, 93 % of the maximum: wide enough that, at quality 75, the largest 4:3 photo inside it has 14.8 times the pixels of the smallest.
If the best result under 300,000 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 300 KB
At quality 75, each kind of image lands in the 20–300 KB window from the first size up to the second.
| Image | Reaches 20 KB at | Stays under 300 KB up to |
|---|---|---|
| Head-and-shoulders portrait | 309 × 385 | 1,700 × 2,123 |
| Outdoor landscape (12 MP phone photo) | 321 × 240 | 1,232 × 924 |
| Scanned typed document page | 304 × 382 | 1,450 × 1,822 |
| Handwritten letter with signature | 539 × 443 | 2,407 × 1,978 |
| Flat-colour graphic (flag) | 785 × 549 | 6,164 × 4,314* |
Fixed pixel sizes against 20–300 KB
When the form fixes the pixels, the file lands in the 20,480–300,000 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 300 KB |
|---|---|---|
| 413 × 531 (35 × 45 mm at 300 DPI) | 45 | 95+ |
| 600 × 600 (2 × 2 inch at 300 DPI) | any (30 reaches it) | 95+ |
| 800 × 600 (4:3 web photo) | any (30 reaches it) | 95+ |
| 1080 × 1080 (square social post) | any (30 reaches it) | 73 |
| 1200 × 1600 (3:4 portrait upload) | any (30 reaches it) | 88 |
| 1920 × 1080 (Full HD frame) | any (30 reaches it) | 39 |
| 1240 × 1754 (A4 page at 150 DPI) | any (30 reaches it) | 80 |
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 (3 % of the pixels that still fit under 300 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 1,232 × 924 quality 75 lands inside 20–300 KB.
Every size in the table reaches 20 KB by quality alone, so within 20–300 KB padding is only for smaller crops.
Upload sizes against 20–300 KB at quality 75
413 × 531 (about 31.2 KB), 600 × 600 (about 45.5 KB), 800 × 600 (about 121 KB), 1240 × 1754 (about 252 KB), 1200 × 1600 (about 170 KB) land inside 20–300 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 300 KB: 1080 × 1080 (about 307,000 bytes), 1920 × 1080 (about 536,200 bytes), which need a lower quality or fewer pixels.
Inside 20–300 KB at quality 75, a handwritten page runs from 539 × 443 to 2,407 × 1,978 pixels and a portrait from 309 × 385 to 1,700 × 2,123.
How to compress an image to 20–300 KB
-
Open the tool above
Preset: minimum 20 KB, maximum 300 KB, JPG.
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Add the image
Drop, paste or pick it; the 20,480–300,000 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).
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Download
name-300kb.jpg; compare its byte count with 20–300 KB.
Forms that ask for 20–300 KB
Upload specs in our dataset with exactly this window. Verify with the official notice before you submit.
20–300 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 20 KB and 300 KB?
Use the tool on this page, preset to 20–300 KB: it returns a JPG of 20,480 to 300,000 bytes. A 4:3 photo stays under 300 KB up to about 1,232 × 924 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 20–300 KB, so it needs padding: opt in, and a JPEG comment segment adds the missing bytes without touching the picture.
Is a 156 KB file inside 20–300 KB?
Yes: anything from 20,480 to 300,000 bytes passes under both KB definitions. Exactly 307,200 bytes passes only where 1 KB = 1024 bytes.
Which pixel size lands between 20 KB and 300 KB?
At quality 75: a photo from about 321 × 240 to 1,232 × 924, a portrait from 309 × 385 to 1,700 × 2,123.
Related
Single limits
- Compress to 16 KB
- Compress to 20 KB Maximum only
- Compress to 25 KB
- Compress to 250 KB
- Compress to 300 KB Maximum only
- Compress to 350 KB
Ranges sharing a limit
Pixel sizes under 300 KB
- 1200×900 landscape about 278 KB as a quality-75 JPG
- 900×1200 portrait about 278 KB as a quality-75 JPG
- 1366×768 (WXGA) about 270 KB as a quality-75 JPG