Why Is My PDF So Big? A Practical Guide to PDF File Size
A ten-page PDF can be 200 KB or 60 MB. The difference almost never comes from the text. It comes from images, and especially from scans and phone photos. Once you know what is inside your file, choosing the right way to make it smaller is straightforward.
What takes up space in a PDF
| Content | Typical size | Comment |
|---|---|---|
| Text-only page | A few KB to 50 KB | Text is stored as characters plus fonts, which is very compact. |
| Page with a few charts or a logo | 50 to 300 KB | Depends on whether graphics are vector drawings or pictures. |
| Scanned page | 300 KB to 3 MB | Every scan is a picture, even when it looks like text. |
| Phone photo of a page | 1 to 6 MB | Modern phone cameras capture far more detail than a document needs. |
Embedded fonts also add size, usually tens or hundreds of kilobytes per font, but they are rarely the main problem.
Before compressing: remove what you don't need
The cheapest kilobyte is the one you delete. Blank pages from a duplex scanner, duplicate covers, and appendices the recipient doesn't need can be taken out with Remove pages. If a portal has a per-file limit, splitting the document into parts is sometimes better than compressing it hard.
How Compress PDF on Maher PDF works
Being clear about the method helps you decide when to use it. Compress PDF redraws each page and saves it as a JPG image at the level you pick:
- Low: best quality, moderate reduction. Choose this when the document has small print.
- Medium: the default, and a good balance for most scans.
- High: smallest file, visibly softer. Fine for photos and large-print documents.
Because every page becomes an image, three things change in the result: text can't be selected, copied, or searched; links stop working; and form fields are flattened. In return, scans and photo-heavy files often shrink dramatically, and the tool shows you the size before and after.
When compression helps and when it doesn't
It helps with scanned documents, PDFs built from phone photos, and image-heavy brochures. These files usually store far more image detail than a reader can see.
It doesn't help with PDFs that are mostly typed text, such as reports exported from Word. These are already small, and turning their pages into pictures can make them bigger. If the status line shows a larger result, keep the original.
Don't use it when the recipient needs to search the text, fill in a form, or click links. Send the original through a cloud link instead.
Tips for smaller files from the start
- When scanning paperwork, choose 150 to 200 DPI and greyscale unless colour matters. 600 DPI colour scans are huge and rarely needed.
- When exporting from Word or Excel, use the standard or "minimum size" PDF option for email copies.
- When photographing documents with a phone, avoid zooming in on details you don't need; frame just the page.
- For a multi-page photo scan, use Scan to PDF and then compress once at the end, rather than compressing every image separately.
Email and upload limits to keep in mind
Most email services cap attachments at around 20 to 25 MB, and many company mail servers set lower limits. Online application portals often allow only 2 to 10 MB per file. Check the specific limit and aim comfortably below it, since some systems count encoded size, which is larger than the file size on disk.
Summary
Look at what is in the file first. Remove unneeded pages, split if a per-file limit is the issue, and compress when the document is mostly images and nobody needs to select its text. Keep the original whenever you compress.