How to get a PDF under 10MB for an upload form
Right before a deadline, a message like "files must be under 10MB" can be stressful. A PDF built from phone photos or scans easily reaches 20 to 30MB with only a handful of pages. This guide walks through how to cut the size while keeping every page readable.
1. Why PDFs get heavy
Most of a PDF's size comes from images, not text. A text-based PDF can be dozens of pages and still under 1MB, but in a scanned PDF each page is a photo, often 2 to 5MB per page. So shrinking a PDF is mostly about making those images lighter.
2. Check what kind of PDF you have
Open the PDF and try to select some text with your mouse. If individual words highlight, it is a text PDF. If the whole page is selected as one block, or nothing is selected, it is an image (scanned) PDF.
- Text PDF: try Light mode first. Quality and searchable text stay intact, but since the file is already light, it may not shrink much.
- Image PDF: Strong mode works best. Pages are redrawn at the resolution you choose, usually ending up at 10 to 40% of the original size.
3. Choosing Strong mode settings
| Situation | Resolution | Image quality |
|---|---|---|
| Documents that will only be read on screen | 110dpi | 60% |
| Documents a reviewer might print | 150dpi | 70% |
| Still over the limit | 72dpi | 50%, grayscale |
Start with 110dpi at 60% quality, then open the result and zoom in to check that small print is still readable. For documents that do not need color, switching to grayscale alone saves a lot. Keep in mind that after Strong mode you can no longer select or search the text.
4. Still too big? Split it
If you simply have a lot of material, compression alone may not be enough. If the form accepts several files, use PDF Split to divide it into parts such as "main documents" and "supporting evidence". Number the file names so the reviewer knows the order.
5. Start light when you create the PDF
If you are making the PDF from phone photos, the cleanest option is to pick a lower image quality from the start. In the Image to PDF tool, choose Smaller file and you often will not need a separate compression step.
Final checklist
- Did you open the compressed file and confirm every page is there?
- Did you zoom in to check that stamps, signatures and small print are readable?
- Did you keep a copy of the original file?
Compression happens entirely in your browser, so documents with personal information are never uploaded to a server.