Compress PDF and Reduce File Size Online
Shrink a PDF file size while keeping quality readable.
How to Compress a PDF in 3 Steps
- Upload your PDF. Click "Choose file" or drag and drop your PDF into the upload area. Files up to 50MB are supported. Larger files with many images will see the greatest compression benefit.
- Click "Compress PDF". PDFTools automatically applies maximum compression settings — downsampling embedded images and optimising the PDF structure to achieve the smallest possible file size.
- Download your compressed PDF. Your compressed file is ready in seconds. Image-heavy PDFs typically see 60-90% size reduction. Text-only PDFs see a smaller reduction since text data is already compact.
Why Use PDFTools to Compress PDF?
- Maximum compression applied automatically — PDFTools uses aggressive Ghostscript compression settings — no sliders or settings needed. The tool picks the best compression for your file.
- Dramatically smaller file sizes — Image-heavy PDFs typically reduce by 60-90%. A 10MB scanned document often compresses to under 1MB, making it easy to email or upload.
- No watermarks added — Unlike many free PDF compressors, PDFTools never stamps watermarks on your compressed files. What you get is your own document, just smaller.
- Completely free — Compress as many PDFs as you need, as often as you need, completely free. No account, no subscription, no limits.
Frequently Asked Questions
How much will my PDF be compressed?
The compression ratio depends on the content of your PDF. Image-heavy documents (scans, presentations, photo books) typically compress by 60-90%. Text-only documents see a smaller reduction, often 10-30%, since plain text is already very compact data.
Will compressing reduce the quality of my PDF?
PDFTools uses a high-compression setting that lowers image resolution to approximately 72-100 DPI. This is fine for screen reading and email attachment but may reduce print quality for high-resolution documents. The text content is always preserved at full quality.
Why is my PDF still large after compression?
If your PDF contains many high-resolution embedded images, compression can only reduce size so far while the file remains readable. For very large PDFs, consider also splitting the document or reducing the number of pages using the Split PDF or Delete Pages tools.