A PDF that is too large to email is one of the most common document headaches. This guide explains why PDFs balloon in size and how to reduce them for free, without uploading your file or destroying its quality.
Why is my PDF so big?
Most oversized PDFs are large for one of these reasons:
- High-resolution scanned pages stored as full-size images.
- Photos embedded at camera resolution when a fraction would do.
- Redundant data left behind by the program that created the file.
How to compress a PDF
Open the Compress PDF tool and choose a mode. Lossless optimises the file structure with zero quality change — best when you need selectable text. Strong re-encodes pages as optimised images for the biggest reduction, ideal for scans and image-heavy documents.
PDF10x shows the original size, the new size and the percentage saved, so you know exactly what you gained — and the whole thing runs in your browser, so the file is never uploaded.
Extra ways to shrink a PDF
- Delete pages you do not need with Remove Pages before compressing.
- Split a huge document into parts with Split PDF and send them separately.
- If you only need the visuals, export pages as images with PDF to JPG.
How small can I make it?
For scanned documents, Strong mode often cuts the size by 60–90%. For files that are already well optimised, savings are smaller — but you can always trim pages or split the document to get under a strict email limit.