Why PDF files get so big
Most of a PDF’s weight is pictures. A scan or a slide deck full of photos can reach 20 MB or more, while a text-only file stays tiny. Fonts that are embedded several times and leftover editing data add a little more.
What you can safely reduce
- Image resolution: around 150 dpi looks sharp on a screen and is plenty for reading. Keep 300 dpi only if you plan to print.
- Image quality: JPEG at 70 to 80 percent is hard to tell from the original.
- Duplicate and hidden data from earlier edits.
Step by step
- Open the PDF compressor and add your file. It runs in your browser, so the file is not uploaded.
- Pick a level. Start with the lighter setting and check the result before you go smaller.
- Download the new file and zoom in to check small text and pictures.
- If it is still too large, compress again with a stronger setting or split the PDF into parts.
Hitting a size limit
Email services usually accept attachments of about 20 to 25 MB, and many online forms allow far less. If a form asks for a file under a set size, try the 100 KB, 200 KB or 500 KB tools, which aim for that size directly.
What to avoid
Do not compress the same file again and again, because each pass can lower image quality. Keep the original and compress from it. For scanned text that must stay readable, avoid the smallest setting.
Choosing the right setting
If the PDF is mostly text, almost any setting keeps it sharp, so pick the strongest one. If it is full of photos, try the middle setting first. For scans of contracts or receipts, keep enough quality that the smallest print is still readable when you zoom in to 150 percent.
A quick checklist
- Keep the original file until you have checked the result.
- Open the compressed PDF and scroll through every page.
- Check signatures, stamps and small tables.
- Rename the new file so you do not send the wrong one by mistake.