What actually makes a PDF heavy
Three things dominate: embedded fonts, full-resolution images, and inefficient internal structure from the exporting application. Structural rewriting is safe and reversible in the sense that nothing visible changes, which is what this tool does.
If a document is still enormous afterwards, the weight is in its images. Export the source at a lower image resolution, or convert the pages to compressed images if fidelity matters less than size.
When to compress
Before emailing (most servers cap attachments at 10-25 MB), before uploading to a portal with a size limit, and before archiving large batches. Keep the original if the document is a print master.
Frequently asked questions
Does compressing reduce quality?
- No. Structural compression leaves page content byte-identical; only the file's internal organisation changes.
Is my document uploaded?
- No. Compression runs entirely in your browser.
How much smaller will it get?
- Typically 5-30%, depending on how the PDF was generated. Image-heavy scans benefit least.