Government portals, exam forms, banks and job sites often limit uploads to 100 KB, 200 KB or 1 MB. A phone scan of a single page can easily be 2–5 MB, so you need to shrink it a lot without making the text unreadable. Here is how to do it, starting with the quickest method.
Why some PDFs are so large
Almost all the size of a scanned PDF comes from the images inside it. A photo from a modern phone is 12 megapixels or more, far more detail than a printed page needs. Text-only PDFs made from Word or Google Docs are usually small already; if one is large, embedded fonts or pictures are the reason.
Method 1: Compress the PDF
- Open Compress PDF and add your file.
- Start with the Recommended level and check the new size.
- If it is still too big, try High compression, then open the result and zoom to 100% to make sure small text is still clear.
Compression shrinks the images inside the PDF while keeping text and vector graphics sharp, so it works best for scans and image-heavy documents.
Shrink a PDF in your browser. Nothing is uploaded.Open Compress PDF →Method 2: Rebuild a scan from images
If the PDF is a scan and still too big, rebuild it from smaller images. You keep control of exactly how much detail is kept:
- Use PDF to Image to turn each page into a JPG at 100–150 DPI. (If you have the original photos, skip this step.)
- Crop away the background around the page with Crop Image; empty table or floor around the paper wastes bytes.
- Combine the pages with Image to PDF, using a lower image quality.
A clear A4 page of text is often between 50 and 150 KB this way. Grayscale pages are smaller than colour, so for black-and-white documents scan or convert in grayscale.
Method 3: Split the PDF
If the form allows more than one file, or only needs some pages (say, the first page of a certificate), use PDF Splitter to upload only the pages that matter. Each smaller file is then much easier to get under the limit.
Rough sizes to expect
| Document | Typical size after compression |
|---|---|
| 1-page text PDF from Word or Docs | Under 100 KB (often 20–60 KB) |
| 1-page scan, grayscale, 150 DPI | About 50–150 KB |
| 1-page scan, colour, phone camera | About 150–500 KB |
| 10-page scanned document | About 1–3 MB |
What not to do
- Do not shrink until it is unreadable. An officer who cannot read your marks or ID number may reject the application. Always check the result at 100% zoom.
- Do not upload sensitive documents to random websites to compress them. Tools on this site run entirely in your browser, so files never leave your device.
- Do not rename a file to change its type. Renaming photo.jpg to photo.pdf does not make it a PDF; convert it with Image to PDF.
Frequently asked questions
Why is my compressed PDF not much smaller?
If it is mostly text and vector graphics, there is little to compress. Very small PDFs, or PDFs whose images are already compressed, also shrink less. Try Method 2 for scans.
Is 100 KB the same as 0.1 MB?
Roughly. Many sites count 1 KB as 1,024 bytes, so 100 KB is 102,400 bytes. Aim a little below the limit, such as 90–95 KB, to be safe.