Compress a PDF to 100 KB
100 KB is a tight limit, and most of the documents asked to meet it are scans. Here is what fits, and what to do when it does not.
Where 100 KB comes from
- Indian government recruitment and examination portals, which commonly cap each uploaded document between 50 KB and 200 KB.
- Older university and scholarship forms built around dial-up-era limits that were never revised.
- Any form that asks for a document and a photograph separately, and gives the document the smaller allowance.
What actually fits in 100 KB
Worked out from what this tool produces, not from a rule of thumb. Where a row says no, it says what to do instead.
| What you have | Fits in 100 KB? | What it takes |
|---|---|---|
| 1–3 pages of text, exported from Word | Comfortably | Nothing — the lossless pass alone usually does it, and the text stays selectable |
| A CV with a photo and a logo | Usually | One re-encode; the photo loses detail you would need to zoom in to see |
| One scanned page, black and white | Yes | Around 100 dpi — readable on screen, soft in print |
| One scanned page, colour photograph of a document | Tight | Expect visible softness; scan it in greyscale instead if you can |
| Three or more scanned pages | No | Split the document and upload the pages separately, or rescan in greyscale |
If your PDF is a photo of a page taken with a phone, the single biggest saving is not compression — it is scanning it in greyscale at 150 dpi in the first place. A colour phone photo starts around 3 MB; the same page scanned properly starts under 300 KB.
Text that was real text stays real text as long as the lossless pass is enough. Below about 150 KB on a scan, the page is a picture either way, so nothing is lost that was not already lost.
Questions
- Will the text still be selectable at 100 KB?
- If your PDF came out of a word processor and the lossless pass gets it under 100 KB, yes — nothing about the pages changes. If the file has to be re-encoded to fit, the pages become images and the text stops being selectable. The result says which of the two happened.
- What if it will not go under 100 KB?
- You get the smallest version it could make, and a note saying what it managed. At that point the only real lever left is fewer pages: upload the pages you were actually asked for, or send the rest separately.
- Is my document uploaded anywhere?
- No. The compression runs inside this browser tab, so the file never leaves your device — which also means a 100 KB limit on a slow connection costs you nothing to experiment with.
A different limit?
Every one of these opens the same tool with a different number in the box. If the limit you were given is not here, open Compress PDF and type it in.