Compress PDFs (and why text-only PDFs barely shrink)

You can compress PDF files offline in 1FileTool by re-encoding the images inside them — the document never leaves your Mac. A photo-heavy scan or brochure can shrink dramatically, while a text-only report barely changes, because there is nothing in it to re-encode.

Run the compressor

1. Open PDF Tools › Compress — it also appears as PDF Compress on the site.
2. Drop one PDF or a whole folder onto the drop zone. Every file in the batch is compressed with the same settings.
3. Pick a Quality level — Low, Medium or High. The control reads "Lower quality means smaller files."
4. Press Compress (or Run on N PDFs for a batch) and check the result card: it shows the new size and the percentage saved.

Each finished file lands next to the original as <name>_compressed.pdf — or wherever Replace source / your output folder sends it.

What the quality levels do

Compression re-encodes the image streams embedded in the PDF as JPEGs. The three levels map to JPEG quality settings: High keeps the most image detail, Low pushes the smallest files. Text, fonts and page structure are copied through untouched — only the pictures inside change.

If the re-encoded file would come out larger than the original, the compressor keeps the original instead. A run can never make a PDF bigger.

Why a text-only PDF barely shrinks

A contract or report that is all vector text has no embedded images to re-encode, so the "after" file is nearly the same size. That is expected — the tool is working, it just has nothing to squeeze. For those files:

• If the PDF is many pages you only need part of, extract or delete pages instead — see Merge, split and reorder.
• If it started life as a scan, the page images are what make it big — re-running compression with Low quality has the most effect on scans.
• If images inside are already efficient, the file is about as small as the format allows.

Batch compression

Dropping a folder compresses every PDF inside it, one result card per file. The per-file saving and the total are shown on the results, and the run can be cancelled mid-batch.

Related

• Merge, split, reorder and number pages
• OCR a scanned PDF to text
• PDF to Word: visual vs text mode
• Compress and resize images in bulk
• Output folder and Replace source
• Why files never upload