Why is my PDF so large?
A PDF is a container. Text takes almost no space, but images do. A single phone photo can weigh 3 to 5 MB, and a scanned document is nothing more than one large image per page. That is why a 10-page scan often reaches 20 MB while a 100-page report written in Word stays under 1 MB.
Other culprits are embedded fonts, high-resolution logos repeated on every page and files exported with “print quality” settings.
Email attachment limits to keep in mind
- Gmail: 25 MB per message (all attachments combined).
- Outlook / Microsoft 365: usually 20 MB, sometimes less on company servers.
- Yahoo Mail: 25 MB.
- Administration and job-application portals: often 2 to 5 MB per document.
Also remember that attachments are encoded when they are sent, which makes them about a third larger. Aim for a file comfortably below the limit.
Compress your PDF in three steps
- Open the free Compress PDF tool.
- Select your file. Choose Recommended compression: it keeps text sharp while strongly reducing photos.
- Click Compress PDF and download the result. The new size and the percentage saved are shown immediately.
Your file is processed in your browser: it is never uploaded to a server, which matters when you are compressing a pay slip, an ID card or a medical report.
Which compression level should I choose?
- Light: for documents you will print or that contain small text and detailed charts.
- Recommended: the best balance for email and online forms.
- Strong: when a portal imposes a very small size (2 MB or less). Text stays readable on screen.
Still too big? Three more tricks
- Remove unnecessary pages (blank pages, annexes) with Remove pages before compressing.
- Split the document into several emails with Split PDF.
- Scan in grayscale next time: a black-and-white scan is typically three times lighter than a color one.
Does compression reduce quality?
Compression works by re-encoding images at a lower resolution. On screen the difference is usually invisible at the recommended level. If the compressed file were larger than the original — this happens with PDFs that are already optimized — Helpdf simply keeps your original file.