Compress PDF to 100 KB

🔒 Runs in your browser — files are never uploaded

Get a PDF under the 100 KB limit that exam boards and government portals insist on. Nothing is uploaded — which matters when the document is your certificate or ID.

How it works
  • Select your PDF. The target is already set to 100 KB.
  • Click Compress PDF and wait — the tool works out how much compression the limit requires.
  • Open the downloaded file and check it is still readable before you submit it.

Why 100 KB, and why it is so hard

The 100 KB ceiling comes almost entirely from government and examination portals — recruitment boards, university admissions, licensing authorities. The limits were set when connections were slow and have never been revisited, so candidates uploading a phone scan of a certificate routinely arrive with a 3 MB file against a 100 KB cap. That is a thirty-fold reduction.

It is achievable, but only within limits worth understanding before you start.

The page-count problem

This is the thing that decides whether you succeed. A PDF's size is roughly the sum of its pages, so 100 KB is a budget split across however many pages you have:

PagesBudget per pageResult
1~100 KBComfortable. Text stays crisp.
2–3~35–50 KBFine for typical documents. Slight softening.
5~20 KBNoticeably soft. Small print may struggle.
10+~10 KB or lessNot realistically legible.

So before compressing harder, check how many pages the form actually requires. If it wants a degree certificate and you are uploading a six-page transcript, remove the pages you don't need. Cutting six pages to one turns an impossible target into an easy one.

If it is one photographed document, don't use a PDF compressor at all. Compress the photo to about 90 KB with the image compressor, then convert it to PDF. You get a visibly better result than compressing a PDF built from a full-size photo, because you avoid re-encoding the image twice.

Photograph it properly and the problem shrinks

Much of the file size in a bad scan is noise the compressor has to spend data encoding: shadows, background clutter, an uneven angle. A clean capture is smaller before you compress anything.

  • Even daylight, no flash, no shadow across the page.
  • Phone held parallel to the document, not tilted.
  • Fill the frame with the document — crop out the desk.
  • Use your phone's document scanner (Notes on iPhone, Google Drive on Android) rather than the plain camera. It flattens the background to clean white, which compresses far better than a photograph of a page.

Before you submit

Open the compressed file at 100% zoom and read the smallest text on it — a registration number, a date, a signature. If you cannot read it, neither can the person reviewing your application, and a rejected submission costs far more than another five minutes here. If it fails that check, reduce the page count rather than accepting an illegible file.

Frequently asked questions

How do I compress a PDF to under 100 KB?
Select your file with the target set to 100 KB and click Compress. If it cannot reach the limit, the document almost certainly has too many pages — remove the ones the form does not require and try again.
Why do exam forms insist on 100 KB?
The limits date from an era of slow connections and constrained storage, and have generally never been raised. Portals reject anything over the stated size outright, so the file has to fit.
My PDF has 10 pages and won't compress to 100 KB. What now?
That is about 10 KB per page, which cannot stay legible. Remove the pages the form does not need. Most applications want one or two specific documents, not an entire transcript.
What if I only need to submit one photographed certificate?
Skip the PDF compressor. Compress the photo itself to around 90 KB, then convert that to PDF. Avoiding the double re-encode gives a noticeably sharper result.
Will the compressed file still be accepted?
Yes — it is a normal, valid PDF. The only thing that changes is that the pages are images rather than text, which portals accept without issue.
Is my PDF uploaded to a server?
No. The whole thing runs in your browser — pages are rendered locally, re-encoded, and rebuilt into a new PDF on your device. Nothing is transmitted, which matters because the documents people compress are usually ID scans, certificates and bank statements.
Will the text still be selectable afterwards?
No. Compression works by turning each page into an image, so text becomes pixels. That is fine for submitting a form, where a human or a scanner reads the document either way, but keep your original if you need a searchable copy.
Does it work on scanned documents?
That is exactly what it is best at. A scan is already a picture, so re-encoding it loses almost nothing visible while cutting the file dramatically. Text-based PDFs compress well too, but lose their selectable text.