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Compress an image to 300 KB
To get an image under 300 KB, PixelFit aims at 300,000 bytes or less, so forms counting 1 KB as 1000 or 1024 bytes both accept it. Estimated from our measured encodes, that is about 1,232 × 924 pixels for a 4:3 photo at quality 75, or 1,700 × 2,123 for a portrait.
Under 300 KB
JPG · under 300 KB (at most 300,000 bytes) · original pixel size · white background
PixelFit aims at 300,000 bytes or less, so the file passes whether the form counts 1 KB as 1,000 or 1,024 bytes.
Fit, background and padding white background
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.
What 300 KB means in bytes
300 KB is 307,200 bytes when 1 KB = 1024 bytes (300 × 1024) and 300,000 bytes when a server counts 1 KB = 1000 bytes. The 7,200-byte gap matters only near the limit. PixelFit aims at 300,000 bytes or less and prints the exact byte count, so you can compare it with the form.
300 KB is 0.29 MB; 34 such files fit in 10 MB. Uncompressed, the 1,232 × 924 photo that fits here would need 3.26 MB of raw pixels, so JPEG at quality 75 packs it about 11 to 1.
Largest pixel size that fits 300 KB
The biggest image of each kind, in its own aspect ratio, that stays at or below 300,000 bytes.
| Image | JPG q60 | JPG q75 | JPG q90 | WebP q75 |
|---|---|---|---|---|
| Head-and-shoulders portrait | 2,067 × 2,581 | 1,700 × 2,123 | 1,193 × 1,490 | 2,610 × 3,259* |
| Outdoor landscape (12 MP phone photo) | 1,425 × 1,068 | 1,232 × 924 | 978 × 733 | 1,315 × 986 |
| Scanned typed document page | 1,772 × 2,226 | 1,450 × 1,822 | 1,019 × 1,280 | 2,221 × 2,790 |
| Handwritten letter with signature | 3,004 × 2,469* | 2,407 × 1,978 | 1,639 × 1,347 | 3,832 × 3,150* |
| Flat-colour graphic (flag) | 6,743 × 4,720* | 6,164 × 4,314* | 4,939 × 3,457* | over 9,561 × 6,692 |
A 12 MP phone photo at 300 KB
Our 12 MP landscape sample (4032 × 3024) is about 4.15 MB at quality 90, 15 times the 300 KB budget; even quality 30 leaves 1.26 MB (extrapolated from encodes up to 3,000 px). So the pixels must go down too.
At about quality 75 it fits 300 KB near 1,232 × 924 (1.1 MP, 9 % of the original pixels). Quality 60 allows 1,425 × 1,068; quality 90 needs 978 × 733.
JPEG quality for fixed pixel sizes under 300 KB
When a form fixes the pixels, only quality can move. Highest quality (of 100) that keeps each size at or under 300,000 bytes:
| Pixel size | Measured on | JPG | WebP |
|---|---|---|---|
| 800 × 600 (4:3 web photo) | landscape photo | quality 95+ (263 KB) | quality 95+ (242 KB) |
| 1080 × 1080 (square social post) | landscape photo | quality 73 (288 KB) | quality 78 (288 KB) |
| 1200 × 1600 (3:4 portrait upload) | portrait photo | quality 88 (282 KB) | quality 92 (264 KB) |
| 1920 × 1080 (Full HD frame) | landscape photo | quality 39 (289 KB) | quality 36 (289 KB) |
| 1240 × 1754 (A4 page at 150 DPI) | scanned typed page | quality 80 (292 KB) | quality 90 (281 KB) |
| 2480 × 3508 (A4 page at 300 DPI) | scanned typed page | no: fewer pixels needed | quality 57 (290 KB) |
Measured JPEG files either side of 300 KB
Real encodes from our test set at quality 75: the largest file that stays under 300,000 bytes and the smallest that goes over.
| Image | Largest under 300 KB | Smallest over 300 KB |
|---|---|---|
| Head-and-shoulders portrait | 1601 × 2000: 268,967 B | 1922 × 2400: 374,872 B |
| Outdoor landscape (12 MP phone photo) | 1200 × 900: 284,926 B | 1600 × 1200: 498,311 B |
| Scanned typed document page | 1273 × 1600: 244,883 B | 1592 × 2000: 346,869 B |
| Handwritten letter with signature | 2400 × 1973: 298,321 B | 3000 × 2466: 455,963 B |
| Flat-colour graphic (flag) | 3000 × 2100: 115,604 B | none: every measured size fits |
JPG, WebP or PNG at 300 KB
At quality 75, WebP holds 1,315 × 986 of the landscape photo in 300 KB, JPG 1,232 × 924: 14 % more pixels. Portrait gain: 136 % (extrapolated). Typed page gain: 135 %. A moderate gain for the landscape photo at 300 KB, a large one for portraits and typed pages: where WebP is accepted, use it for those. Many portals accept only JPG/JPEG, so this page starts in JPG.
A full-colour PNG is lossless, so its size follows the content. In 300 KB it holds a flat graphic of 5,180 × 3,626 (extrapolated) pixels but a photo of only 449 × 336, against 1,232 × 924 as a quality-75 JPG. Reducing a PNG to a palette of up to 256 colours (PixelFit does this when a PNG must shrink) helps graphics far more than photos.
Which uploads fit comfortably in 300 KB
3 of the 6 sizes above keep quality 75 or better under 300 KB (800 × 600, 1200 × 1600, 1240 × 1754); 1 misses even at quality 30 (2480 × 3508). At 1,232 × 924, quality 90 costs 60 % more bytes than quality 75.
A typed page reaches 1,772 × 2,226 at quality 60 in 300 KB, about 190 DPI if it is an A4 sheet.
How to compress an image to 300 KB
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Open the tool above
It is preset to 300 KB (300,000 bytes or less), JPG output.
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Add your image
Drop, paste or pick it; a PNG, WebP or (where the browser opens it) HEIC file becomes a JPG under 300 KB.
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Pixel size: only if asked
On auto, a typical photo stops near 1,232 × 924 at about quality 75.
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Download and check
name-300kb.jpg comes with its byte count, pixels and quality.
Forms that ask for 300 KB
Upload specs in our dataset with exactly 300 KB. Verify with the official notice before you submit.
300 KB limits
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 300 KB?
Drop it into the tool here, preset to 300 KB. It searches JPEG quality (at most 8 encodes per pixel size), then scales pixels down if needed, until the file is 300,000 bytes or less. A 4:3 photo typically lands near 1,232 × 924 at about quality 75.
How do I compress an image to less than 300 KB without losing quality?
Give up pixels before quality: at quality 75, 300 KB holds 1,232 × 924 of a photo and 1,700 × 2,123 of a portrait; quality 90 at 1,232 × 924 costs 60 % more bytes.
Is 300 KB 300,000 or 307,200 bytes?
Both readings exist: 307,200 bytes (1 KB = 1024) or 300,000 bytes (1 KB = 1000). 300,000 bytes or less passes both.
Can I compress a PNG to 300 KB?
Yes, but a full-colour PNG photo stays big: about 449 × 336 pixels in 300 KB, versus 5,180 × 3,626 (extrapolated) for a flat graphic. As a JPG the photo reaches 1,232 × 924.
What pixel size fits 300 KB?
At quality 75: a photo 1,232 × 924, a portrait 1,700 × 2,123, a typed page 1,450 × 1,822.
Related
Nearby file sizes
- Compress to 250 KB photo ≈ 1,128 × 846
- Compress to 240 KB photo ≈ 1,106 × 829
- Compress to 200 KB photo ≈ 1,015 × 761
- Compress to 350 KB photo ≈ 1,334 × 1,000
- Compress to 400 KB photo ≈ 1,429 × 1,071
- Compress to 500 KB photo ≈ 1,603 × 1,202
More ways to hit 300 KB
- JPG to PDF under 300 KB One image as a PDF
- Between 20 KB and 300 KB Minimum and maximum
- Image resizer with KB target Any size, pixels and format
Pixel sizes that fit 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
- 1024×1024 square about 270 KB as a quality-75 JPG