Compress PDF to 100 KB: Squeeze a one-page scan or form under 100 KB. Input: PDF, image files and values you enter. Output: Results shown on the page and a downloaded file. Privacy: Runs in your browser: inputs and files stay on your device and are not uploaded.
How to compress a PDF to 100 KB
- Drop your PDF, or several PDFs and photos of documents, on the box. They are combined into one file in the order you add them.
- The target is already set to 100 KB. Tick Black and white if colour is not needed.
- Press Compress to target. The tool picks the best quality that still fits and shows a before and after preview.
- Check that the text is readable, then download.
What fits in 100 KB
A 100 KB limit leaves room for about one scanned page at a readable resolution, or a few pages of plain text kept as text. Black and white can help here. If the target cannot be reached without making text unreadable, the tool tells you and offers the smallest readable version.
The limit is counted in decimal units (1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes), so the file is accepted whichever way a website counts. Everything runs in your browser; nothing is uploaded.
Example: two files under 100 KB
A 10-page report with text, charts and photos (677 KB) came out at 96.7 KB. Every word stayed selectable and searchable, and the pages looked almost the same as before: an SSIM similarity score of 0.997, where 1 means identical. Ghostscript, set to lower its image resolution step by step, could not get the same file below 150 KB.
An 8-page PDF of phone photos (9.3 MB) also fitted, at 93 KB, but at that size the photos look soft. For photos, keep only the pages that are asked for, or use a bigger target if the form allows it.
How it compares with free PDF sites
| This tool | iLovePDF (free) | Sejda (free) | |
|---|---|---|---|
| File size | Your device memory | 200 MB | 50 MB, 200 pages |
| Tasks per day | No limit | Not stated | 3 |
Free-plan limits as published by each service (checked 21 October 2026): iLovePDF pricing, Sejda pricing. They change often; the paid plans lift them.
FAQ
Where would I need a PDF under 100 KB?
On strict application portals that give each supporting document, such as a certificate or proof of address, its own small upload box. The limit is normally printed next to the box or in the instructions for the form, so check it there, along with any minimum size.
Is 100 KB enough for a readable page?
For one page, yes, in black and white. 100 KB is very little room for colour or several pages: tick Black and white, keep only the page that is asked for, and crop the scan to the document edges.
What if the tool says 100 KB cannot be reached?
It then offers the smallest version that is still readable. Splitting the document, removing pages or rescanning with better light (a cleaner white background compresses better) usually closes the gap.
Is 100 KB counted as 100,000 or 102,400 bytes?
The tool aims for 100,000 bytes, the smaller of the two, so the file passes whichever way the website counts.
Can a PDF with several pages fit in 100 KB?
Often, yes. Our 10-page test report with text and charts fitted, and its text stayed selectable. Pages full of photos fit too, but look soft at that size: tick Black and white or keep fewer pages for a clearer result.