How This PDF Compressor Works
The tool rebuilds your PDF inside your browser and saves it using compressed object streams, a feature of the PDF format that packs the document’s internal structure more efficiently. It also drops unused objects and leftovers from earlier edits that many PDF editors leave behind. Your pages, text and images are copied across unchanged, so there is no loss in visual quality.
Because nothing is re-encoded, the amount of reduction depends on how the original file was made. Documents exported from office software, forms and files that have been edited many times often shrink noticeably. PDFs that are mostly high-resolution photos or scans are dominated by image data and may only get slightly smaller.
How to Compress a PDF
- Choose or drag in the PDF you want to shrink.
- Click Compress. Processing happens on your device, so even large files never leave your computer.
- Compare the original and new sizes, then download the compressed copy.
More Ways to Reduce PDF Size
- Remove pages you do not need with Split PDF before compressing.
- For scanned documents, rescan at 150–200 DPI in grayscale instead of 600 DPI color — this is usually the biggest single saving.
- When exporting from Word or other editors, choose the “minimum size” or “standard” option instead of “high quality print”.
- Avoid embedding full fonts when the recipient does not need to edit the file.
Why Private, In-Browser Compression Matters
Many online compressors upload your file to their servers. That can be a problem for contracts, payslips, medical records or anything with personal data. Here the file is read and processed by your own browser, and the result is saved directly to your device.
Frequently Asked Questions
Will compression reduce the quality of my PDF?
No. This tool only optimizes the file structure; it does not resample or re-compress images, so text and images look exactly the same.
Why did my file barely get smaller?
The file was probably already well optimized, or most of its size comes from images. For image-heavy scans, re-scanning at a lower resolution will save far more space.
Is there a file size limit?
There is no fixed limit, but because everything runs in your browser, very large files (hundreds of megabytes) depend on your device’s available memory.
Are my files uploaded anywhere?
No. The PDF is processed locally in your browser and is never sent to a server.