How to get a PDF under 100KB (without it looking terrible)
By The CompressImages Team
You've filled out the form, scanned your documents, and hit upload — and the site spits back that familiar red error: *file too large, maximum 100KB*. Government portals, visa applications, job boards, and university systems are weirdly obsessed with that number, and a scanned PDF almost never starts anywhere near it.
The good news is that getting under 100KB is usually a 20-second job. The slightly annoying news is that there's a point where squeezing harder just makes everything blurry, so it helps to know where that line is.
The quick way
Drop your file into Compress PDF, switch to target-size mode, and type 100. That's it — the tool keeps lowering the image quality in steps until the output lands at or below your number, then stops. If you already know you need exactly 100KB, the compress PDF to 100KB page skips the setup and goes straight there.
What's actually making your PDF big
Nine times out of ten, it's images. A page of plain text is tiny — a few kilobytes. But the moment you scan a document or paste in a photo, you're carrying around a high-resolution image, and those add up fast. That's why a three-page scanned contract can be 8MB while a thirty-page text report is 400KB.
Knowing this changes how you compress. If your file is mostly scanned pages, you can drop the image resolution a lot before anyone notices. If it's a designed document with sharp logos, go gentler.
When 100KB just isn't realistic
Sometimes the target is too aggressive for what you've got — say, ten scanned pages crammed under 100KB. At that point you've got two honest options:
- Split the file. If the form takes multiple uploads, use Split PDF to break a long document into smaller pieces that each slip under the limit.
- Rescan at a lower setting. Scanning in grayscale at 150 DPI instead of colour at 600 DPI can cut the size by 80% before you even open a compressor.
Tip — If the text in your result looks soft, you compressed one step too far. Re-run it with a slightly higher target — 120KB often looks noticeably cleaner than 100KB, and plenty of forms that say '100KB' actually accept a little more.
A note on privacy
If you're compressing passports, bank statements, or anything with your signature on it, it's fair to care where the file goes. Everything here runs over an encrypted connection and the uploaded file is deleted automatically a short while after it's processed — we're not keeping your documents around.
Once your file fits, you're done. No account, no watermark stamped across page one, no catch.