Compress PDF to 100KB
Shrink big PDFs for email and upload limits, with an optional target size in KB.
- ✓Files never uploaded
- ✓No file limits
- ✓No sign-up
- ✓No watermark
A 100 KB limit is one of the strictest you'll meet, and it usually shows up on government portals, exam and job application forms, and older HR systems that were built when storage was expensive. This page opens the compressor with the target size already set to 100 KB. Drop your PDF, click Compress PDF, and the tool tries progressively stronger settings until the file fits under the limit. It all happens in your browser, so your ID card scan or certificate never leaves your device.
What's realistic at 100 KB? A one- or two-page scanned document — an identity card, a certificate, a signed form — usually compresses to that size while staying perfectly readable. A 10-page scan is much harder, because 100 KB spread across ten pages leaves only about 10 KB per page. If the result looks too blurry, cut the document down to the pages the form really needs with Extract Pages or Remove Pages, then compress again.
It helps to start from a clean source. Scan in black and white or grayscale rather than color when color isn't required, crop out the empty background around a card or receipt, and avoid scanning at extreme resolutions like 600 DPI. Keep in mind that compressed pages become images, so text won't be selectable afterwards — that's fine for scans, but keep your original file too. If the portal accepts a slightly bigger file, the 200 KB or 500 KB targets will give noticeably sharper results.
Before you submit, open the compressed file and zoom in on names, dates and ID numbers to make sure every detail an official needs to check is still legible. If anything is unclear, try again with fewer pages rather than stronger compression.
How to Compress PDF
- 1Drop your PDF into the box or click to choose it.
- 2Pick a compression level: low, medium or high.
- 3Optionally enter a target size in KB, such as 500.
- 4Click Compress PDF and the smaller file downloads automatically.
Why pdfdots?
Private by design
All processing happens locally in your browser. Your documents are never uploaded to a server, so nobody else can see them.
No limits
No daily task caps, no file-count limits and no premium tier. Process as many PDFs as your device can handle.
Fast
There's no upload or download queue. Work starts the moment you drop a file and finishes at the speed of your own computer.
Works everywhere
Windows, Mac, Linux, iPhone, Android or Chromebook — if it has a modern browser, pdfdots runs on it. Nothing to install.
What the compression levels actually do
pdfdots compresses a PDF by re-drawing each page as an optimized JPEG image and building a new PDF from those images. This is very effective on the files that are usually the biggest problem: scanned documents, phone photos of paperwork and PDFs full of high-resolution pictures. A 20 MB scan often drops to a small fraction of that size. Low keeps the most detail, medium is a good balance for most documents, and high produces the smallest file with visibly softer images.
There's an honest trade-off to know about. Because pages become images, text in the compressed file is no longer selectable or searchable, and links stop being clickable. For a scanned document that doesn't matter — it was an image anyway. For a text-heavy report exported from Word, compression may not shrink it much and you'd lose the selectable text, so keep the original as well.
If you have a hard limit, such as a portal that only accepts files under 500 KB, type that number in the target size field. The tool then tries progressively stronger settings to get the file at or under the target. Very long documents may not reach extremely small targets while staying readable; in that case, split the file or remove unneeded pages first. Everything runs on your own device, so even confidential documents are never uploaded.
Our take
Compress PDF is our go-to when an upload form has a hard limit, typically a job portal, a university application or a government site that refuses anything above a few hundred kilobytes, and the file in hand is a phone scan.
We start with Medium, because it keeps printed text readable while cutting most scans dramatically. When a portal names an exact limit we type it into the target size field, a little below the stated maximum, so small overhead does not push the file over. High is our last resort for long scans.
The trap: compression turns every page into a JPEG, so a text-based report loses selectable text and may barely shrink. For those files we would rather remove unneeded pages with Remove Pages, or re-export from the original program, and keep the searchable version.
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Frequently asked questions
Can any PDF be compressed to 100 KB?+
Short scanned documents usually can. Long or very detailed files may become hard to read, so reduce the page count first.
What if the result is still over 100 KB?+
Remove unnecessary pages, try the high level, or rescan in grayscale at a lower resolution, then compress again.
Will my document still be readable?+
For one or two pages, generally yes. Check the result before submitting, especially small print.
Is my file uploaded to hit the target size?+
No. All compression attempts run locally in your browser.
How much can a PDF be compressed?+
It depends on the content. Scanned and image-heavy PDFs often shrink by 70–90%, while text-only PDFs may shrink very little.
Why can't I select text after compressing?+
Compression re-renders each page as a JPEG image, so text becomes part of the picture. Keep the original if you need selectable text.
Can I compress a PDF to a specific size?+
Yes. Enter a target size in KB and the tool tries stronger settings until the file is at or below that size, when possible.
Which compression level should I choose?+
Medium suits most documents. Use low if images must stay sharp, and high when the smallest possible file matters most.
Is it safe to compress confidential documents?+
Yes. Compression runs locally in your browser, and the file is never uploaded to a server.
Is there a file size limit?+
No fixed limit. Very large PDFs just take longer and need more memory on your device.