Compress PDF to 100 KB
Get a scanned certificate, ID proof or letter under 100 KB for an upload form. The PDF is compressed on this device and never uploaded.
- 100% free
- Runs in your browser
- No uploads
- Runs on your deviceEvery tool works directly in your browser. No files are uploaded.
- Your privacy mattersYour files never leave your device, so there's nothing for us to store.
- No limitsUse any tool as much as you need. No daily caps, no waiting.
- Completely freeNo signup and no trial to cancel. Ads keep the tools free.
How to compress a PDF to 100 KB
- Add the PDF. Drop it on the box or choose it. You can add several; each is compressed on its own.
- Leave the limit on 100 KB. Fit under a size is already selected. Type another number in Other size if your form differs.
- Compress, check and download. The bar shows the new size against the limit. Open the result and zoom in before uploading it.
When a form asks for 100 KB
100 KB is a tight limit for a PDF. Application portals often use it for single supporting documents such as a certificate, an ID card scan or a signed declaration, where they expect one or two pages.
A scanned page is a picture, and pictures are what take the space. So 100 KB comfortably holds one page, often two, but rarely five pages of colour scans without making them hard to read. If the document is long, check whether the form only needs the relevant page.
What reaches 100 KB, and what doesn't
We ran sample A4 scans through this page in Chrome. Your files will differ, since busy pages and colour need more space, but the pattern holds: page count and colour decide whether 100 KB is realistic.
| Sample file | Before | After | How |
|---|---|---|---|
| 1-page colour scan, 200 DPI | 376 KB | 58 KB | Photos recompressed |
| 2-page greyscale scan, 300 DPI | 1.28 MB | 64 KB | Photos recompressed |
| 3 pages, one with a photo, 200 DPI | 1.36 MB | 96 KB | Photos recompressed |
| 5-page colour scan, 200 DPI | 1.93 MB | 126 KB (didn't fit) | Pages re-rendered at 50 DPI |
When nothing fits, the tool keeps the smallest version and says it couldn't reach the limit, rather than quietly handing you an unreadable file.
If it won't fit
Send only the pages asked for. If a 5-page scan won't fit, use Extract PDF pages to keep the one page the form needs, then compress that.
Rescan in greyscale. Black-and-white documents don't need colour. In the test above, two greyscale pages fit in 64 KB while five colour pages couldn't reach 100 KB at all.
Crop the edges. Dark borders and the scanner lid around the page are pure waste. Scanning apps with a document mode crop them for you.
Other sizes
Frequently asked questions
It says it couldn't get under 100 KB. What now?
You get the smallest version it could make, but it's still over the limit. Remove pages the form doesn't need, rescan in greyscale at 150 to 200 DPI, or split the document if the form lets you upload more than one file. Forcing a long colour scan under 100 KB makes it unreadable.
Is 100 KB counted as 100,000 or 102,400 bytes?
Websites differ, so the tool aims at 100,000 bytes, the smaller of the two. A file that passes here passes either way.
Will the text stay readable at 100 KB?
For one or two pages, usually yes. Open the result and zoom into the smallest print, stamps and signatures before you upload it. If the tool had to turn pages into images, the note under the file says at what resolution.
Does my PDF get uploaded?
No. Compression runs in your browser using your device's processor. That matters for ID scans and certificates, which carry personal details.