Compress a PDF to under 100 KB
For portals with a tiny PDF limit: certificates and ID scans under 100 KB, made on your device.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Get a scanned certificate, ID or mark sheet under 100 KB for an exam, job or scholarship portal. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
Exam boards, recruitment sites and scholarship portals often cap each document at 100 KB: a caste or income certificate, a degree certificate, an identity card, a single mark sheet. A phone scan of one page is usually 1 to 3 MB, so it has to lose nine tenths of its size.
This page tries the gentlest route first: a lossless rewrite, then lighter recompression of the scanned image inside the PDF. For a one-page scan, 100 KB usually needs the page turned into a picture at 90 or 72 DPI, often in grayscale, and the result card says exactly which step was used. Printed text stays readable at those settings; fine print and stamps are worth checking before you upload.
Split a multi-page file first if the portal wants one page per upload: the limit is much easier to meet per page than for a whole document.
How it works
- Drop the scanned PDF.
- Keep 100 KB, or type the limit the portal gives.
- Press Compress to 100 KB and check the text is still legible.
In your browser, not on a server
Lossless cleanup rewrites the PDF with pdf-lib using compressed object streams. Image recompression uses pdf.js to find embedded images, re-encodes each one at a lower quality on a canvas, and pdf-lib swaps the new streams in. Flatten renders every page to an image at the resolution you pick. Each mode runs entirely in your browser.
Compared with upload-based tools: PDF compressors online are the most upload-hungry tools there are, because the whole document has to go up before anything happens. Here a 50 MB scan is processed without a single byte leaving your machine.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
It still comes out over 100 KB.
That happens with several pages or a colourful full-page photo. Split the PDF with the split tool and upload page by page if the portal allows it, or crop the scan to the document edges before making the PDF, so blank table surface does not use up the budget.
Will the portal reject a flattened PDF?
Portals check the size and that the file opens as a PDF; a flattened page is a normal PDF with a picture of the page, which is exactly what a scanner produces. Only forms you must fill in online need real text fields.
Is my certificate kept anywhere?
No. The PDF is opened and rewritten inside your browser tab. Nothing is uploaded, which matters for identity and caste documents that should not sit on a stranger’s server.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after one visit to save itself for offline use; then you can turn off Wi-Fi and it still works.
More PDF tools
Compress PDF
Shrink a PDF for email or an upload limit. Pick a level, or type the size you need, like 1 MB, and the page tries the gentlest setting that fits. Processed on your device.
File Checksum
Get a file's checksum on your device and compare it with the one the publisher lists.
JSON ↔ CSV
Paste or drop your data, choose a direction and get a table or an array back. What you paste stays on this device.
Merge PDF
Combine PDFs into one document and set the order with the arrows. No watermark, nothing uploaded, and the size limit is your device’s memory (phones hold less).
Other conversions
Guides
- How to compress a PDF without losing qualityWhere the size comes from, which reductions are free, and where the quality trade-off actually starts.
- Is Smallpdf safe?Smallpdf is a reputable Swiss company with published retention rules. What changes the answer for you is which of its storage rules applies to your file.
- How to resize a PDFTwo different jobs share this name: changing the paper size, and making the file smaller. Here is which is which, and how to do each.
- How to make a PDF black and whiteChoosing black and white when you print only changes the paper. If a portal or a printer wants the file itself in black and white, you need a converted copy.
- Is iLovePDF safe?iLovePDF is an established European service with good published practices. For confidential PDFs, the safer question is whether they need to be uploaded at all.