Updated 31 October 2026 · how we check

JPG to PDF under 20 KB

To make a PDF under 20 KB, PixelFit compresses the JPG to at most 19,264 bytes and wraps it in a one-page PDF with about 736 bytes of PDF structure, 20,000 bytes or less in total. Measured: an A4 scan fits up to 41 DPI at quality 50; a 4:3 photo at about 310 × 232 pixels (quality 75).

PDF under 20 KB

PDF · under 20 KB (at most 20,000 bytes) · original pixel size · white background

PixelFit aims at 20,000 bytes or less, so the file passes whether the form counts 1 KB as 1,000 or 1,024 bytes.

Choose photos or drop them here JPG, PNG, WebP, GIF, BMP, AVIF or SVG, and HEIC where the browser opens it. You can also paste. Nothing is uploaded.

Max size (KB)

Min size (KB)

Format

Width

Height

Unit

DPI

Fit, background and padding white background · page the size of the picture

Fit to the size

Background

PDF page

If the file ends up below the minimum, pad it with an invisible JPEG comment block (the picture is not changed).

Saving presets is part of Pro.

Pick a photo to fit it to under 20 KB (at most 20,000 bytes).

The result appears here: the exact byte count, pixel size and quality, the size before and after, a preview and a download button.

Where the 20 KB go in a JPG-to-PDF file

Of the 20,000 bytes that pass as 20 KB under both KB definitions, PDF structure takes 736 bytes for one A4 page (computed with PixelFit's own writer), leaving 19,264 bytes, 96.3 %, for the JPEG; ten pages leave 1,476 bytes each.

For one photo, quality 75 allows 310 × 232 pixels and quality 90 240 × 180; a full 12 MP frame must be scaled down first, which the tool does for you.

How many pages fit in a 20 KB PDF

The 20,000 bytes of 20 KB, less 736 bytes of PDF structure for the first page and about 500 for each extra one, shared evenly.

Pages	JPEG bytes per page	Max A4 DPI at q50	Max A4 DPI at q75	A4 at 150 DPI
1 page	19,264	41 DPI	33 DPI	no: 6.5× over at q30
2 pages	9,384	29 DPI	23 DPI	no: 13.4× over at q30
3 pages	6,089	23 DPI	18 DPI	no: 20.6× over at q30
5 pages	3,453	17 DPI	13 DPI	no: 36.3× over at q30

Make a PDF under 20 KB →

Phone photos in one PDF under 20 KB

Largest 4:3 photo per page, in pixels, when 1 to 10 photos share 20,000 bytes; "full" means a 12 MP phone photo keeps all its pixels (the tool never enlarges).

Width × height in pixels. * = outside the measured range (100 to 3000 px long edge), extrapolated.
Photos	Quality 60	Quality 75	Quality 90
1 photo	362 × 271	310 × 232	240 × 180
2 photos	247 × 185	214 × 160	163 × 122
3 photos	196 × 147	166 × 124	127 × 95
5 photos	138 × 103	118 × 88	91 × 68*

A4 and Letter pixel sizes against 20 KB

One typed page per DPI: its pixels, the quality it gets alone in 20 KB, and how many fit at quality 75.

DPI	A4 pixels	One A4 page under 20 KB	Letter page	Pages at q75
72 DPI	595 × 842	no: 2.0× over at q30	no: 1.9× over at q30	none
100 DPI	827 × 1169	no: 3.5× over at q30	no: 3.4× over at q30	none
150 DPI	1240 × 1754	no: 6.5× over at q30	no: 6.4× over at q30	none
200 DPI	1654 × 2339	no: 9.8× over at q30	no: 9.6× over at q30	none
300 DPI	2480 × 3508	no: 17.6× over at q30	no: 17.2× over at q30	none

Readable pages and photos in 20 KB

20 KB holds a full typed A4 page only as a low-resolution scan: about 41 DPI (339 × 479 pixels) at quality 50, where a line of 12-point type is about 7 pixels tall, hard to read. A 72 DPI scan (595 × 842) is 2.0 times too big even at quality 30.

What fits at a readable 150 DPI is a crop: a full-width strip about 23 mm high (8 % of the page, roughly 4 lines of 12-point type at single spacing) at quality 50. For a certificate or mark sheet, crop to the part the form needs before you convert.

Under 20 KB a full 150 DPI A4 scan gets nothing: even quality 30 is 6.5 times too big, and no photo of 1600 × 1200 fits at quality 70.

One image free, several merged with Pro

Free: each image becomes its own one-page PDF under 20 KB. Pro: several images merged into one PDF under 20 KB, on your device; 2 pages get 9,384 bytes of JPEG each.

How to turn a JPG into a PDF under 20 KB

Open the tool above

Preset: PDF output, at most 20 KB.
Add the JPG

Drop, paste or pick it (PNG, WebP and HEIC work too).
Choose the page

Keep the picture's own size or fit it on A4 or Letter.
Download

name-20kb.pdf arrives with its exact byte count (20,000 bytes or less).

Forms with a 20 KB PDF limit

Upload specs in our dataset with a PDF limit of exactly 20 KB. Verify with the official notice before you submit.

20 KB PDF uploads

ICSI student

Sources

Measured by PixelFit with sharp 0.35.5 / libvips 8.18.7 on 31 October 2026.
Samples, Wikimedia Commons, checked 31 October 2026: typed page (public domain) commons.wikimedia.org/w/index.php?curid=194775753; landscape (CC0 1.0) commons.wikimedia.org/w/index.php?curid=154070378
Paper sizes, Markus Kuhn, checked 31 October 2026: cl.cam.ac.uk/~mgk25/iso-paper.html
PDF format, Library of Congress, checked 31 October 2026: loc.gov/preservation/digital/formats/fdd/fdd000474.shtml

Frequently asked questions

How do I convert a JPG to PDF under 20 KB?

Drop the JPG into the tool on this page, preset to PDF under 20 KB: the picture is compressed to 19,264 bytes or less, so the PDF ends at or below 20,000 bytes.

Can I convert JPG to PDF for free?

Yes, one image per PDF, with no upload. Under 20 KB a 4:3 photo keeps 310 × 232 pixels at quality 75; merging several JPGs is Pro.

How many pages fit in a 20 KB PDF?

Under 20 KB, not even one full A4 page at 150 DPI keeps quality 50; a whole page fits only at about 41 DPI, so crop to the part you need (a full-width strip about 23 mm high at 150 DPI).

What DPI should a scan have for a 20 KB PDF?

None of the usual 72 to 300 DPI settings keeps a full A4 page at quality 50 under 20 KB: the limit is about 41 DPI. Scan at 150 DPI and crop to the needed part instead.

Why is the PDF bigger than my JPG?

A PDF wraps the JPEG in page, image and cross-reference objects: 736 bytes for one page in PixelFit's writer, about 500 more per added page.

Other PDF size limits

JPG to PDF under 30 KB one cropped image
JPG to PDF under 40 KB one cropped image
JPG to PDF under 50 KB one cropped image

More for 20 KB

Compress an image to 20 KB Same limit, image output
JPG to PDF: what changes Format facts
Image resizer with KB target Any size and format

Other formats to PDF

Pixel sizes that fit 20 KB

120×600 banner about 18.7 KB as a quality-75 JPG
256×256 icon about 17.1 KB as a quality-75 JPG
728×90 banner about 17.1 KB as a quality-75 JPG

Index

PDF under a size: all 21 pages