Measure a structural rewrite before expecting a big reduction
The example PDF starts with uncompressed text drawing commands. The structure rewrite reduces it from 6,009 to 5,308 bytes and retains two pages. This small test is not representative of a scanned document.
- Input
- 6,009 bytes
- Output
- 5,308 bytes
- Result
- 2 pages
Settings: Preferred maximum 0.1 MB; Optimize PDF.
Download input · Download measured output
Measured with this site’s processing engine in Edge 156 on 27 October 2026. These are results for this sample, not promised sizes for other files. Browser encoders can produce different byte counts. How to repeat the examples
| What makes the PDF large? | What to expect here | If it remains too large |
|---|---|---|
| Unoptimized document structure | A rewrite may reduce overhead | Compare measured bytes and inspect all pages |
| Photographs or scanned pages | Image resolution is not automatically lowered | Re-export smaller images in the source/scanning application |
| Already optimized content | Little reduction, or a larger output | Keep the smaller original |
A “Valid PDF produced” message confirms a readable output structure, not that the preferred maximum was met. Read the warning and actual byte count before deciding which file to keep.
Before you accept the download
- Open the saved file and check A1 followed by A2 in the sample.
- Compare input and output bytes; keep the smaller usable file.
- Check searchable text, form fields and visual layout when working with your own documents.
- Digitally signed PDFs are rejected because rewriting would invalidate their signatures.
How it works
Three clear steps
- 01
Choose a valid, unrestricted PDF.
- 02
Optionally set a maximum target and start optimization.
- 03
Review the achieved size; download only if the result is useful.
What this tool does
A conservative structure pass reports the achieved size honestly and never rasterizes every page by default.
How this result is produced
A local, conservative PDF rewrite optimizes document structure without rasterizing every page or bypassing passwords and restrictions. The achieved size is reported even when no useful reduction is possible.
Practical example
For a PDF that must be under 5 MB, set that maximum and compare the verified result. A photo-heavy or already optimized PDF may not shrink enough safely.
Limits and troubleshooting
- Browser-only structure optimization may not reduce image-heavy or already optimized PDFs.
- Password-protected, encrypted, malformed, or oversized files are rejected; restrictions are never bypassed.
A scan made mostly of full-page photographs may barely shrink during a structure-only pass. For a much smaller copy, return to the scanner or source application and reduce image resolution there before creating a new, unrestricted PDF.
Questions people ask
Why did my PDF not get smaller?
The document may already be optimized or dominated by embedded images that cannot be safely recompressed without rasterizing pages. The tool reports this instead of claiming success.