"File exceeds the maximum size of 20 MB." "Maximum allowed size: 5 MB." Anyone who works with PDFs knows these messages — and the question that follows: is there a PDF size limit? How many pages fit in 10 MB?
The short answer: the PDF format has no limit you will hit in practice — PDFs of hundreds of megabytes and thousands of pages open normally. The limit comes from the system receiving the file. And how many pages fit under each limit depends far less on the number of pages than on the type of page.
Who sets the limit: the most common ones
| Where you are sending it | Typical limit per file |
|---|---|
| Gmail | 25 MB per email (larger attachments become a Google Drive link) |
| Outlook | Usually 20 MB |
| Court e-filing systems | Varies by court and system — often between a few MB and a few dozen MB per document |
| University, job and government portals | Often 1 to 10 MB, sometimes less |
| WhatsApp (as a document) | Large files are accepted; the real limit is usually the recipient's phone |
Limits change and vary between installations — always check the system's own message. What matters is knowing how much you need to cut.
How much does one PDF page weigh?
This is why a 10-page PDF can weigh 15 MB while a 300-page one weighs 2 MB:
| Page type | Approximate weight per page |
|---|---|
| Text generated straight from Word or a system | 10 to 100 KB |
| Text with a logo and a few small images | 50 to 300 KB |
| Black-and-white scanned page | 50 to 200 KB |
| Greyscale or colour scanned page (150–200 dpi) | 200 KB to 1 MB |
| High-resolution colour scan (300 dpi or more) | 1 to 5 MB |
| Full-page phone photo | 2 to 8 MB |
These are rough ranges — the real weight depends on the scanner, the compression and the content.
How many pages fit in 5, 10 or 25 MB?
Doing the maths with the ranges above:
| Limit | Digital text | B&W scan | Colour scan |
|---|---|---|---|
| 5 MB | hundreds of pages | 25 to 100 pages | 5 to 25 pages |
| 10 MB | hundreds to thousands | 50 to 200 pages | 10 to 50 pages |
| 25 MB | thousands | 125 to 500 pages | 25 to 125 pages |
To know your own case, do the reverse calculation: file size ÷ number of pages = average weight per page. A 40 MB PDF with 80 pages has 0.5 MB per page — it is a colour scan, and compression will pay off.
What to do when the system rejects your file
1. Compress the PDF
This is the first thing to try and it solves most cases. In RoseLab's Compress PDF, you see the size of two versions before downloading:
- Light compression (lossless): keeps text selectable and the original quality. Good for text PDFs with a few images;
- Image compression: rebuilds each page as an optimised image. Reduces a lot — the right choice for scans — but text is no longer selectable.
Everything happens in your browser, without uploading the document. More in how to compress a PDF without losing quality.
2. Split it into parts
When the limit is very low (1–3 MB) and the document has many scanned pages, even the best compression is not enough. The answer is to split the PDF into volumes — by page ranges or every N pages — and send each part separately. A step-by-step for court filings is in how to split a PDF into parts for electronic filing.
3. Remove what does not need to go
Blank scanner pages, cover sheets, duplicated pages: removing pages reduces the size and leaves a cleaner document.
4. Fix it at the source
If the PDF comes from a Word file full of photos, compressing the Word file before exporting gives a better result — see how to reduce the size of a Word file. And if you are going to scan again, 150–200 dpi greyscale is usually enough for text documents; 300 dpi colour is only needed for photos and documents where colour matters.
Why a "small" PDF can suddenly grow
- Printing to PDF an existing document can turn text into images and enlarge the file;
- Merging a scanned PDF with others adds up — the total is the sum of the parts;
- Saving with "optimise for print" in some programs increases image resolution;
- Digitally signing adds little (a few KB), but each new signature adds a layer to the file.
Frequently asked questions
Does PDF have a maximum file size? Not for everyday use: very large PDFs open normally on modern computers. The limits you run into are set by the systems receiving the file (email, courts, portals).
How many pages is a 25 MB PDF? It depends on the page type: thousands of pages of digital text, or roughly 25 to 500 scanned pages, depending on colour and resolution. Divide your file size by the number of pages to get the average.
How do I get a PDF under 5 MB? Start with light compression; if that is not enough, use image compression. If it is still over the limit, split it. Text PDFs almost always fit under 5 MB; colour scans may need both steps.
Does compressing a digitally signed PDF invalidate the signature? Yes — the compressed file is new and the signature does not come along. Compress before signing. See what the warnings on a signed PDF mean.
The portal accepts up to 20 MB and my PDF is 21 MB. What is fastest? Light compression, or removing two or three unnecessary pages, usually solves it in seconds without touching quality.
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