How to make a PDF smaller
Updated:
Large PDFs are almost always caused by images — scanned pages, photos or high-resolution graphics. The most effective levers are storing images at a lower resolution, removing unneeded pages and choosing the right scan settings from the start.
Why is my PDF so large?
- Scans: every page is a photo — in color at 300 DPI, easily several hundred kilobytes per page.
- Photos: phone photos have many megapixels and are often embedded unchanged.
- Embedded fonts: usually a small share, but noticeable with many fonts.
- Leftovers: PDFs edited many times can carry duplicate, unused objects.
1. Compress
With Compress PDF you choose between lossless optimization (“Light”) and re-rendering pages at a lower resolution (“Recommended”, “Strong”). The tool keeps the smallest result automatically.
2. Remove unneeded pages
Blank backsides, ads or attachments nobody needs: delete them in a few clicks with Organize PDF.
3. Split
If the whole document must still be sent, split it into several files with Split PDF.
4. Scan smarter
| Setting | Recommendation for documents |
|---|---|
| Resolution | 150–200 DPI for screen and email; 300 DPI only for print or OCR |
| Color mode | grayscale or black & white when color isn’t needed |
| File format | scan straight to PDF, not TIFF |
5. Shrink images first
When building a PDF from photos, reduce them first with Resize images. For an A4 or Letter page, 1500–2000 pixels on the long side are usually enough.
6. Re-export
If you have the original in Word or another program, export again with a setting like “Optimize for screen” or “Minimum size”.