PDFMintHow to Reduce PDF File Size: 7 Practical Ways
A PDF that's too large gets bounced by email, rejected by upload forms and takes ages to open on a phone. The good news: most oversized PDFs are big for one of a few simple reasons, and each has a quick fix.
Why is my PDF so big?
In most cases the culprit is images. A single phone photo can be 3–5 MB, so a 10-page document made from photos easily reaches 30 MB or more. Other causes are embedded fonts, high-resolution scans (600 DPI when 150 would do), and files that were saved many times with leftover data.
1. Use an online compressor
The fastest fix is a compressor such as PDFMint Compress PDF. Pick “Recommended” for a good balance, or set a target size like 200 KB if a form has a strict limit. Scanned and photo-based PDFs typically shrink by 50–90%.
2. Start from smaller images
If you are building a PDF from photos, it's better to shrink the images before they go into the PDF. Image to PDF has a “Maximum file size” option that does this automatically.
3. Scan at the right resolution
For documents you'll read on screen or upload, 150 DPI in greyscale is usually plenty. 300 DPI is only needed for printing photos or fine print. Halving the DPI cuts file size to roughly a quarter.
4. Remove pages you don't need
Blank pages, duplicate pages and cover sheets add weight. Remove them with Delete PDF pages.
5. Split the document
If a portal accepts several uploads, split the PDF into parts that each fit the limit.
6. Export again from the original
If you have the original Word or PowerPoint file, export to PDF again and choose “Minimum size” or “Optimise for online publishing”. This keeps text sharp and selectable.
7. Use “Print to PDF” as a last resort
Printing a PDF to a new PDF (Ctrl/Cmd + P › Save as PDF) sometimes strips hidden data. Results vary, so compare the size afterwards.
Quick reference
| Situation | Best fix |
|---|---|
| Form says “max 100 KB” | Compress to 100 KB |
| PDF made from phone photos | Re-create with Image to PDF and a size limit |
| Text-only PDF is large | Re-export from Word, or “Light” compression |
| Still too big at lowest quality | Split into parts or remove pages |
Frequently asked questions
Does compressing a PDF reduce quality?
Strong compression lowers image sharpness. “Recommended” settings keep documents clearly readable while removing most of the excess size.
Can I compress a PDF on my phone?
Yes. PDFMint works in mobile browsers and nothing is uploaded.