How to compress a PDF to 100KB
Try the compressor's Keep text mode first: for a typed document it is often enough. If the file is a scan or full of photographs, switch to Rasterise at the Small setting, which shrinks image-heavy pages the most. A single scanned page can often get under 100KB that way; several scanned pages usually cannot, and then the honest fix is to split the file or scan it again in greyscale.
Compress PDF shows the new size before you download, so you know whether you are under the limit. Compress PDF
Getting a PDF under 100KB
- Open the PDF in the compressor and run Keep text selectable first.
- Check the new size. If it is under 100KB, stop there and download.
- If not, switch the mode to Rasterise and choose Small, 110 DPI.
- Look at the sample crop of the busiest page to check the text is still readable.
- Still too big? Split the PDF and upload the pages separately, or scan it again with fewer pages.
Why 100KB is hard
A PDF's size is almost all images. A page of typed text stored as text weighs a few kilobytes, while the same page scanned is a photograph weighing tens or hundreds of kilobytes. That is why a typed letter reaches 100KB easily and a five page scan almost never does.
Upload forms that insist on 100KB or 200KB were usually designed around one scanned page, which is why a document of several pages fights them.
The two settings that matter
Keep text rewrites the file's structure and changes nothing you can see. It helps most on files exported from office software, which often carry unused fonts and objects.
Rasterise draws every page as an image and saves it compressed. Small uses 110 DPI with the strongest compression, Balanced 150 DPI and Careful 200 DPI. For a 100KB target on a scan, Small is usually the one that gets there, and the sample crop shows you whether the result is still legible before you download it.
If it still does not fit
Split it. Many portals accept several files, and Split PDF can turn every page into its own file.
Scan it again, better. A page scanned in greyscale at 150 DPI is far smaller than a colour phone photograph of the same page. Crop to the edges of the paper so no table or floor is included.
Do not shrink past legibility. A form rejected as unreadable costs more time than one rejected as too large.
When the form wants an image instead
Some portals want a JPG of the document rather than a PDF. The same logic applies: fewer pixels and stronger compression. PDF to JPG at 96 DPI produces the smallest page images, which is often small enough on its own.
Questions people ask next
Can I compress a PDF to 100KB without losing quality?
Only when its size comes from structure rather than images, as with many Word exports. For scans and photographs, reaching 100KB always costs some sharpness; what matters is whether it stays readable.
Why did compressing make my file bigger?
Rasterising a typed document can make it larger, because a picture of text weighs more than the text. The compressor says so when it happens, and you should keep your original.
Is my document uploaded when I compress it?
No. Compression runs in your browser and the file stays on your device.
How do I compress a PDF to 200KB or 500KB?
The same steps, and it is easier: Balanced or Careful often gets there with better quality than Small.