Compress PDF to 100KB
Reduce a PDF to under 100 KB for forms and portals that refuse anything bigger. Scans and photos are shrunk, text stays text, and nothing is uploaded.
Free, no sign-up. Everything runs in your browser.
or drop a PDF here
One PDF, up to 100 MB and 500 pages. The result is under 100 KB (99,999 bytes or less).
Your file stays on your device
Need a different size? Compress PDF to 200KB or Compress PDF to 500KB
Step by step
How to use Compress PDF to 100KB
- 1
Choose your PDF
Pick one PDF or drag it onto the box. You see its name and size straight away, and whether it is already under 100 KB.
- 2
Compress
Press Compress to under 100 KB. The tool cleans up the file, then makes the photos and scans inside it smaller, step by step, until it fits.
- 3
Check and download
You see the size before and after and how much was saved. Download the PDF and open it once to check that every page is easy to read.
Overview
About Compress PDF to 100KB
100 KB is one of the tightest limits upload forms use, often for a single certificate, ID card or one-page scan. A phone scan of one page is usually several hundred KB to a few MB, so it has to be shrunk a lot. This tool makes the PDF just small enough to pass, not smaller, so it keeps as much detail as 100 KB allows.
It works in steps. First the file is cleaned up without losing anything: hidden metadata, page thumbnails and leftovers of earlier edits are removed and uncompressed parts are packed. If that is not enough, the photos and scanned pages inside the PDF are made smaller in pixels and saved as JPG at a lower quality. The tool tries the strongest setting first to see whether 100 KB can be reached at all, then searches for the mildest setting that still fits, so the file keeps as much quality as the limit allows.
When shrinking the images is not enough, for example for a PDF that is mostly text with large fonts or a long scan, every page is saved as one compact picture so the file still gets under 100 KB. Pages with photos become a JPG; pages of text become a sharp black-and-white picture, which keeps letters crisp at a very small size. Page order, page size and orientation always stay the same.
Everything runs in your browser: the PDF is not uploaded, and your original file is never changed. You download a new copy.
When it helps
- Upload a scanned certificate, ID card or mark sheet to a form with a 100 KB limit
- Shrink a one or two page PDF made from phone photos
- Make a PDF small enough for a portal that rejects bigger files without saying why
- Reduce a scanned document before sending it on a slow connection
Specs
Supported files and limits
- Works with
- PDF files, including scans and PDFs made from photos
- Largest file
- 100 MB and 500 pages
- Target size
- Under 100 KB means at most 99,999 bytes, so it passes whether a site counts 1 KB as 1000 or 1024 bytes
- What gets smaller
- Photos and scanned images (JPG and most other colour or grey images), plus hidden data. Fonts and text are kept
- Not supported
- Password-protected PDFs (remove the password first). Black-and-white fax-style scans are left as they are because they are already small
- Time limit
- About 3 minutes per file. If it runs out, the best file so far is kept
- Where it runs
- In your browser. Nothing is uploaded
What fits in 100 KB?
A rough guide only. The real result depends on how the PDF was made, how much colour it has and how busy the pages are.
| Likely result | Tip | |
|---|---|---|
| 1 scanned page | Usually fits and stays readable | Scan in good light; a clean white page compresses best |
| 2 to 3 scanned pages | Often fits, with softer detail | Crop away borders and desk before making the PDF |
| 4 or more scanned pages | Fits, at a lower resolution per page | Split the PDF or use 200 KB if the form allows it, for sharper pages |
| Text-only PDF from Word | Fits. If fonts make it too big, pages become sharp black-and-white pictures | Fewer pages keep the text crisper |
Good to know
- The result is always checked: it is only called done when the file really is 99,999 bytes or less.
- If the pages had to be saved as pictures to reach the size, their text can no longer be selected, searched or copied. This only happens when shrinking the images inside is not enough.
- Photos and scans lose some detail. Small print in a scan is the first thing to suffer, so always open the result and check it before you upload.
- Images are saved as colour JPG. Images with transparency masks keep their mask; images in CMYK or special colour spaces are left unchanged.
- Very long files have less room per page. A PDF with dozens of pages fits in 100 KB only at a low resolution; split it if the pages must stay sharp.
Fix a problem
Troubleshooting
The text in my 100 KB PDF looks rough
100 KB is very little for many pages, so each page gets a low resolution. Remove pages you do not need or upload pages separately, so each one keeps more detail.
The scan looks blurry after compressing
100 KB leaves little room. Crop the page tightly before making the PDF, or scan in black ink on white paper so there is less to store.
It says the PDF is password protected
Open it in your PDF reader with the password and save or print it as a new PDF without one, then try again.
The page closed or the browser froze
The file was too big for your device's memory. Close other tabs, use a computer, or split the PDF into parts first.
The portal still says the file is too big
This tool keeps the file under 99,999 bytes. If the portal still refuses it, its limit may be lower than it says; try the next size down, or remove a page.
FAQ
Frequently asked questions
How do I compress a PDF to 100 KB?
Choose your PDF and press Compress to under 100 KB. The tool cleans it up and shrinks the images inside until the file is under 100 KB, then you download it. If shrinking the images is not enough, the pages are saved as compact pictures so the file still fits.
How do I reduce a scanned PDF to 100 KB?
Scans are mostly images, so they shrink well. One scanned page usually fits in 100 KB and stays readable. Several pages may not; then remove pages, split the file, or use the 200 KB tool if the form allows it.
Can a text-only PDF be compressed to 100 KB?
Yes. A PDF of text is often big because of its fonts. If shrinking is not enough, each page is saved as a sharp black-and-white picture, which keeps the letters clear and gets the file under 100 KB.
Can I make a PDF exactly 100 KB?
The tool aims for just under 100 KB, not an exact size. It keeps the best quality that fits, so the result is usually a little below the limit.
Is my PDF uploaded?
No. The PDF is read and compressed inside your browser and never leaves your device, which matters for ID cards, certificates and bank papers.
Is 100 KB counted as 100000 or 102400 bytes?
Sites differ, so the tool keeps the file at 99,999 bytes or less. That is under 100 KB either way. The result shows the size in KB and in exact bytes.
Will my text still be selectable?
Usually yes: first only the images are made smaller and text stays text. If that is not enough to reach the size, the pages are saved as pictures, and then the text can no longer be selected.
Is the original file changed?
No. You download a new copy. The PDF on your device stays exactly as it was.
Is it free?
Yes. Free, no sign-up and no watermark.
Keep going
What to do next
- Does the form allow 200 KB instead? Use Compress PDF to 200KB. Open Compress PDF to 200KB
- Does the form allow 500 KB instead? Use Compress PDF to 500KB. Open Compress PDF to 500KB
- Pages you do not need make the file bigger. Delete them first with Remove Pages. Open Remove Pages
- Too many pages to fit? Upload them in parts made with Split PDF. Open Split PDF
- Making the PDF from phone photos? Build it with Image to PDF, then compress it here. Open Image to PDF
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