Why is my PDF so large?
Updated 23 October 2026 · Zenvoq Labs
| How the page was made | Typical size |
|---|---|
| Exported from Word / Google Docs (text only) | 20–100 KB |
| Scanned at 150 DPI, grayscale JPEG | 60–150 KB |
| Scanned at 300 DPI, colour | 500 KB – 1.5 MB |
| Phone camera photo of a page | 2 – 8 MB |
1. The pages are photos
When you take a picture of a document with a phone and turn it into a PDF, every page carries the full camera image — 12 to 50 megapixels. Form portals only need about 1–2 megapixels to read the text.
2. The scanner resolution is too high
300 DPI is a printing resolution. For on-screen verification, 100–150 DPI is plenty, and halving the DPI cuts the pixel count — and roughly the file size — to a quarter.
3. Colour where grayscale would do
Certificates are black text on white paper. Saving them in colour keeps the paper's tint, shadows and noise, which all cost bytes. Grayscale typically saves another 20–40%.
4. Embedded fonts and duplicated images
PDFs exported from design tools can embed whole font families and repeat the same logo on every page. These are less common in form uploads, but explain large digital PDFs.
How to fix it
Use a compressor that lets you set the exact size limit, such as FramePDF's Compress PDF tool. It re-renders each page at the highest DPI and JPEG quality that still fits, and runs in your browser without uploading the file.
Frequently asked questions
Handle PDFs offline on your phone
FramePDF makes PDFs smaller, combines and reorders pages, and saves any page as a photo — all on your Android phone, without uploading anything.
- Make PDFs smaller
- Edit pages offline
- Save pages to Photos
