How to compress a PDF under 1 MB (or 2, 5 MB) for email and online portals
You are about to send an application or an attachment and the error appears: “The file exceeds the maximum allowed size”. It happens often with email, public-sector portals, competitions, universities and banks, which cap the size of attachments. The good news is that it is almost always fixed in a minute.
Quick answer
- Open the Compress PDF tool.
- Upload the file (drop it or use Select PDF).
- Choose the compression level and press Compress PDF.
- Download the lighter PDF and check that it is still readable.
No sign-up is required, and the file is deleted automatically within 60 minutes.
Which compression to choose
The figures are indicative: the result depends on how heavy the original file is. The names match the items in the Compression level menu.
| Target size | What to do |
|---|---|
| Under 5 MB (email attachment) | High quality (light compression) or Balanced is usually enough |
| Under 2 MB | Balanced |
| Under 1 MB | Maximum compression; if it is a scan, consider rescanning at a lower resolution |
| Under 500 KB | Maximum compression, or remove unneeded pages or split the file |
Why a PDF is so large
- High-resolution scans: each page is an image. A 600 dpi scan weighs far more than one at 150 dpi.
- Unoptimised photos and images: a document full of phone photos grows quickly.
- Embedded fonts and extra content: usually lighter, but they can add up in busy documents.
- Merged files: if you merged several PDFs, the size is the sum of the parts.
If the file is still too large
- Rescan at 150 dpi: that is plenty for on-screen reading (use 200–300 dpi for print or text recognition).
- Remove unused pages, such as blanks or duplicates, with Reorder pages.
- Split the file into two parts with Split PDF, if the portal accepts more than one attachment.
- Do not compress the same file over and over: after the first pass the gains are tiny and quality drops.
Does quality get worse?
With High quality (light compression) or Balanced, usually not: text stays sharp. With Maximum compression, images can lose detail, so always reread the file before you send it, especially if it has signatures, stamps or small numbers.
Is compressing a PDF online safe?
It depends on the service. Before you upload personal documents, check whether files are deleted and how long they stay on the server. On PDF Universal they are removed automatically within 60 minutes and are not available to anyone, nor to AI systems.
Frequently asked questions
How do I get a PDF under 1 MB?
Use Maximum compression. If it is a scan and that is not enough, rescan at 150 dpi or remove pages you do not need.
Does compressing a PDF change the content?
No. The content stays the same. Only the way images and data are stored changes.
Can I compress a PDF from my phone?
Yes. The tool works in the browser on phones and tablets, with no app to install.
Is it free?
Yes, with no registration and no hidden fees.
What if the PDF has a password?
Unlock the file first with Protect / Unlock, then compress it.
Shrink the file and check that it stays readable before you send it.
Compress your PDF now →