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Compress an image to 100 KB
To get an image under 100 KB, PixelFit aims at 100,000 bytes or less, so forms counting 1 KB as 1000 or 1024 bytes both accept it. Estimated from our measured encodes, that is about 717 × 537 pixels for a 4:3 photo at quality 75, or 883 × 1,102 for a portrait.
Under 100 KB
JPG · under 100 KB (at most 100,000 bytes) · original pixel size · white background
PixelFit aims at 100,000 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 100 KB means in bytes
100 KB is 102,400 bytes when 1 KB = 1024 bytes (100 × 1024) and 100,000 bytes when a server counts 1 KB = 1000 bytes. The 2,400-byte gap matters only near the limit. PixelFit aims at 100,000 bytes or less and prints the exact byte count, so you can compare it with the form.
100 KB is 0.10 MB; 102 such files fit in 10 MB. Uncompressed, the 717 × 537 photo that fits here would need 1.1 MB of raw pixels, so JPEG at quality 75 packs it about 12 to 1.
Largest pixel size that fits 100 KB
The biggest image of each kind, in its own aspect ratio, that stays at or below 100,000 bytes.
| Image | JPG q60 | JPG q75 | JPG q90 | WebP q75 |
|---|---|---|---|---|
| Head-and-shoulders portrait | 1,062 × 1,326 | 883 × 1,102 | 631 × 788 | 1,384 × 1,728 |
| Outdoor landscape (12 MP phone photo) | 830 × 622 | 717 × 537 | 562 × 421 | 761 × 570 |
| Scanned typed document page | 853 × 1,071 | 720 × 904 | 538 × 676 | 969 × 1,217 |
| Handwritten letter with signature | 1,678 × 1,379 | 1,358 × 1,116 | 908 × 746 | 2,135 × 1,755 |
| Flat-colour graphic (flag) | 3,046 × 2,132* | 2,689 × 1,882 | 2,043 × 1,430 | 4,963 × 3,474* |
A 12 MP phone photo at 100 KB
Our 12 MP landscape sample (4032 × 3024) is about 4.15 MB at quality 90, 44 times the 100 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 100 KB near 717 × 537 (0.39 MP, 3 % of the original pixels). Quality 60 allows 830 × 622; quality 90 needs 562 × 421.
JPEG quality for fixed pixel sizes under 100 KB
When a form fixes the pixels, only quality can move. Highest quality (of 100) that keeps each size at or under 100,000 bytes:
| Pixel size | Measured on | JPG | WebP |
|---|---|---|---|
| 413 × 531 (35 × 45 mm at 300 DPI) | portrait photo | quality 95+ (72.2 KB) | quality 95+ (54 KB) |
| 600 × 600 (2 × 2 inch at 300 DPI) | portrait photo | quality 93 (93.5 KB) | quality 95+ (80.5 KB) |
| 800 × 600 (4:3 web photo) | landscape photo | quality 63 (95.9 KB) | quality 65 (97.1 KB) |
| 1080 × 1080 (square social post) | landscape photo | no: fewer pixels needed | no: fewer pixels needed |
| 1200 × 1600 (3:4 portrait upload) | portrait photo | quality 44 (97.5 KB) | quality 78 (94.6 KB) |
| 1240 × 1754 (A4 page at 150 DPI) | scanned typed page | no: fewer pixels needed | quality 37 (96.2 KB) |
Measured JPEG files either side of 100 KB
Real encodes from our test set at quality 75: the largest file that stays under 100,000 bytes and the smallest that goes over.
| Image | Largest under 100 KB | Smallest over 100 KB |
|---|---|---|
| Head-and-shoulders portrait | 801 × 1000: 85,857 B | 961 × 1200: 113,785 B |
| Outdoor landscape (12 MP phone photo) | 600 × 450: 69,996 B | 800 × 600: 124,163 B |
| Scanned typed document page | 637 × 800: 81,646 B | 796 × 1000: 117,818 B |
| Handwritten letter with signature | 1200 × 987: 80,051 B | 1600 × 1315: 134,065 B |
| Flat-colour graphic (flag) | 2400 × 1680: 86,029 B | 3000 × 2100: 115,604 B |
JPG, WebP or PNG at 100 KB
At quality 75, WebP holds 761 × 570 of the landscape photo in 100 KB, JPG 717 × 537: 13 % more pixels. Portrait gain: 146 %. Typed page gain: 81 %. A moderate gain for the landscape photo at 100 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 100 KB it holds a flat graphic of 1,981 × 1,386 pixels but a photo of only 258 × 193, against 717 × 537 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 100 KB
2 of the 6 sizes above keep quality 75 or better under 100 KB (413 × 531, 600 × 600); 2 miss even at quality 30 (1080 × 1080, 1240 × 1754). At 717 × 537, quality 90 costs 62 % more bytes than quality 75.
A typed page reaches 853 × 1,071 at quality 60 in 100 KB, about 92 DPI if it is an A4 sheet.
How to compress an image to 100 KB
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Open the tool above
It is preset to 100 KB (100,000 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 100 KB.
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Pixel size: only if asked
On auto, a typical photo stops near 717 × 537 at about quality 75.
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Download and check
name-100kb.jpg comes with its byte count, pixels and quality.
Forms that ask for 100 KB
Upload specs in our dataset with exactly 100 KB. Verify with the official notice before you submit.
100 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 100 KB?
Drop it into the tool here, preset to 100 KB. It searches JPEG quality (at most 8 encodes per pixel size), then scales pixels down if needed, until the file is 100,000 bytes or less. A 4:3 photo typically lands near 717 × 537 at about quality 75.
How do I compress an image to less than 100 KB without losing quality?
Give up pixels before quality: at quality 75, 100 KB holds 717 × 537 of a photo and 883 × 1,102 of a portrait; quality 90 at 717 × 537 costs 62 % more bytes.
Is 100 KB 100,000 or 102,400 bytes?
Both readings exist: 102,400 bytes (1 KB = 1024) or 100,000 bytes (1 KB = 1000). 100,000 bytes or less passes both.
Can I compress a PNG to 100 KB?
Yes, but a full-colour PNG photo stays big: about 258 × 193 pixels in 100 KB, versus 1,981 × 1,386 for a flat graphic. As a JPG the photo reaches 717 × 537.
What pixel size fits 100 KB?
At quality 75: a photo 717 × 537, a portrait 883 × 1,102, a typed page 720 × 904.
Related
Nearby file sizes
- Compress to 90 KB photo ≈ 681 × 510
- Compress to 80 KB photo ≈ 641 × 480
- Compress to 75 KB photo ≈ 621 × 465
- Compress to 120 KB photo ≈ 786 × 589
- Compress to 150 KB photo ≈ 879 × 659
- Compress to 200 KB photo ≈ 1,015 × 761
More ways to hit 100 KB
- JPG to PDF under 100 KB One image as a PDF
- Between 50 KB and 100 KB Minimum and maximum
- Between 20 KB and 100 KB Minimum and maximum
- Between 100 KB and 200 KB Minimum and maximum
- Image resizer with KB target Any size, pixels and format
Pixel sizes that fit 100 KB
- 800×480 (WVGA) about 97.1 KB as a quality-75 JPG
- 51×51 mm photo about 91.6 KB as a quality-75 JPG
- 2×2 inch photo about 91 KB as a quality-75 JPG
- 600×600 square about 91 KB as a quality-75 JPG