How to make a PDF smaller without losing quality
Your PDF is too big to email or upload? Most of the size usually comes from images. Here is why, and seven practical ways to make it smaller.
Why PDFs get so big
Text takes very little space. A 50-page PDF of plain text can be smaller than a single phone photo. What makes PDFs large is almost always images: photos, scanned pages, screenshots and high-resolution graphics.
A scanned page is really a picture of the page. If it was scanned in colour at a high resolution, every page can be a megabyte or more. Ten pages, and your PDF is too big for many email services and upload forms.
1. Compress the PDF
The easiest fix is a PDF compressor, which makes the images inside the PDF smaller while keeping text as text. With Compress PDF, choose a level: Light keeps images almost unchanged, Medium is the best choice for email and forms, and Strong makes the smallest file. You see the new size before you download, and the PDF is never uploaded.
2. Scan at a lower resolution
If you scan documents yourself, 150 DPI is clear enough for reading on a screen, and 300 DPI is good for printing. Scanning text in black and white or grey instead of full colour also makes files much smaller.
3. Save a smaller PDF from the source
If you make the PDF yourself, look for a size option when you save. Office programs such as Word often have a choice like "Minimum size" or "Optimize for online publishing" in the Save as PDF dialog. Image editors usually let you lower the quality when exporting.
4. Shrink images before making the PDF
Making a PDF from photos? Large phone photos make large PDFs. Make the photos smaller first with Resize image or Compress image, then combine them with JPG to PDF.
5. Split it into parts
If a form allows several files, or you can send more than one email, split the PDF with Split PDF. Each part is smaller, and nothing is lost.
6. Remove pages you do not need
Often only a few pages are really needed: the signed page, the summary, one invoice. Use Split PDF with page ranges to keep just those pages.
7. Check fonts and extras
Some PDFs contain full copies of the fonts they use, attachments, or hidden layers. These are usually small compared with images, but they add up. A compressor or the "minimum size" option in your office program often removes or reduces them.
How to keep the quality
- Start with the lightest setting that gets you under the size limit.
- Zoom in on small text and photos in the result before you send it.
- Always keep your original PDF, because compression cannot be undone.