PDF · Practical tutorial
Why PDF compression sometimes saves very little space
Learn what PDF object compression can change and why scanned documents may stay large.
Not all PDFs contain the same kind of data
A PDF may be made mostly of text and vector drawing instructions, or mostly of scanned photographs. These are very different cases for compression. A document with inefficient internal object storage may get smaller when it is rewritten; a scan containing already compressed JPEG images may shrink very little.
What CraftAI's tool does
The Compress PDF utility describes its approach as reserializing PDF objects using compressed object streams. This is different from aggressively re-encoding each embedded photograph. It is therefore sensible to expect varying savings rather than advertise a universal percentage reduction.
Try a controlled comparison
- Make a copy of the original PDF so you can compare results.
- Open the compression tool and choose the copy, staying within its displayed input limits.
- Process and download the output file.
- Check the sizes of both documents and open the result to inspect fonts, drawings, page order and readability.
- If the new PDF is bigger or unchanged, keep the original; compression is not automatically an improvement.
Assume a 2.0 MB report compresses to 1.8 MB. Savings are (2.0 − 1.8) ÷ 2.0 × 100 = 10%. A different 2.0 MB scanned report might remain close to 2.0 MB because its images are already efficiently encoded.
When this is not the right fix
If a PDF is large because it contains high-resolution scans, reducing source image dimensions or capturing pages more efficiently may matter more. If you need to extract a few pages, a split or page-range tool is better than compressing the whole document.
Common questions
Will compression remove visible content?
It should not intentionally delete pages, but any transformation may fail on malformed or unsupported files. Confirm the page count and content afterwards.
Can I make every PDF smaller than 100 KB?
No. There is no honest guarantee for an arbitrary document. Minimum feasible size depends on the content, number of pages and chosen representation.
Keep your original document. For legal, medical or archival files, verify that the processed file preserves everything you need.
Put the steps into practice
The linked utility opens in your browser. Review its current on-page limits and inspect the output before sharing it.
Use Compress PDF →