Compress PDF to 300 KB

Where a 300 KB PDF limit applies

In its Information Bulletin for JEE (Main) 2026, the National Testing Agency (NTA) asks for the scanned Class 10 or equivalent certificate or mark sheet as a PDF between 50 and 300 KB, clearly legible. A disability or UDID certificate, where it applies, has the same 50 to 300 KB range. Source: National Testing Agency: JEE (Main) 2026 Information Bulletin, linked from jeemain.nta.nic.in.

The Government of India's e-Visa application asks for the scanned bio page of the passport, the page with the photograph and details, as a PDF of at least 10 KB and at most 300 KB. Other documents for business and medical visas have the same 10 to 300 KB range. Source: Government of India: e-Visa application, photo and document requirements.

• Class 10 certificates and mark sheets for exam registrations
• The passport bio page for an e-Visa application
• Other supporting documents with a 300 KB cap

Both forms set a floor as well as a ceiling. The tool aims at or under 300 KB with the mildest setting that fits, and it never makes a file larger. A PDF that is already under 300 KB is left as it is, so compare it with the floor too.

If the page is a photo from your phone, crop it to the page before you make the PDF. The background around the document only takes bytes that the page could use.

Budget per page at 300 KB

300 KB is 300,000 bytes, or 2,400,000 bits, for the whole file: every page, image and font and the structure that holds them together. For a scanned document almost all of it goes to the page images. One Letter page at 150 dpi, the Medium level, has 2,103,750 pixels, so a one-page scan gets 1.14 bits per pixel at 300 KB.

The last two columns show the highest resolution on the tool's list at which a full scanned Letter page still gets that many bits per pixel. Quality bands from section 4.5 of Gregory Wallace's paper on the JPEG standard, which rates color images of moderate detail; he notes that results vary with the content, so read them as a cautious guide for scans. A4 is about 3% larger than Letter.

The steps the tool tries for 300 KB

The tool does not guess from a table: it compresses the real file and measures it. These are its ten steps, from mild to strong, with the pixel size of a full Letter page at each resolution and the number of such page scans that 300 KB holds at 0.5 bits per pixel.

Which PDFs fit in 300 KB

A one-page scan keeps 0.5 bits per pixel, which Wallace's guide rates good to very good, up to 200 dpi. Ten scanned pages still get there at 60 dpi. A PDF of text, like a letter or an invoice exported from a word processor, has no page images, so it fits or not depending on its fonts and text, and this tool copies those unchanged.

Some images stay as they are, because recompressing them would change them or gain nothing: images under 12 KB (12,288 bytes), black-and-white scans stored with fax-style compression (CCITT or JBIG2), JPEG 2000 images, images with a stencil or color-key mask, CMYK images, and flat graphics like logos and charts unless they shrink a lot in pixels. A recompressed image also has to be at least 10% smaller than the original, or the original is kept.

When 300 KB is out of reach

• If the PDF is already at or under 300 KB, the tool says so and you can send the original as it is.
• If it has no images the tool can recompress, it tells you right away that 300 KB is out of reach.
• If even the strongest step, 50 dpi at JPEG quality 30, stays above 300 KB, you see the smallest size it reached. When text, fonts and other parts alone take more than 300 KB, the message says how much. If that smallest version is at least 3% smaller than the original, you can still download it.

Then send fewer pages or split the document: cut out pages with Split PDF or drop the ones you do not need with Delete PDF Pages, and compress each part.

300 KB in bytes

The tool counts 300 KB as 300,000 bytes and stays at or under that. Counted in units of 1,024 bytes, the same limit is 292.97 KB or 0.286 MB, so the file also passes a form that counts that way.

Getting a PDF under 300 KB

Drop a PDF above. The target is already set to 300 KB. Press Compress PDF and the tool first runs its strongest step to check that 300 KB can be reached. If it can, it searches its steps for the mildest one that fits, from 300 dpi at quality 85 down, which takes three or four more runs. Text, fonts, links and form fields are copied unchanged. When the result uses 72 dpi or less, the tool asks you to zoom in and check that scanned text is still easy to read.

Need a different limit? One size down is 200 KB, one size up 500 KB. Type any size into the target field, or use the PDF compressor with Low, Medium or High compression. To combine files first, use Merge PDF; to turn photos of a document into a PDF, JPG to PDF.

Sources

• National Testing Agency: JEE (Main) 2026 Information Bulletin, linked from jeemain.nta.nic.in
• Government of India: e-Visa application, photo and document requirements
• Gregory K. Wallace: The JPEG Still Picture Compression Standard, section 4.5 (copy hosted by the National University of Singapore)

Frequently asked questions