How much file size reduction can I expect from PDF compression?

Savings depend on the original PDF and selected preset. Large scanned pages may shrink, while compact text-only PDFs may become larger. The tool shows measured input and output sizes after processing.

What is the difference between the three compression levels?

Extreme uses page scale 0.75 and JPEG quality 45%; Recommended uses scale 1 and quality 68%; Low uses scale 1.25 and quality 85%. Lower settings trade image detail for a potentially smaller file.

Will compression make the text blurry or unreadable?

Text can become less sharp because every page is converted to an image. Selectable text, links, and interactive forms are not preserved. Keep the original PDF when those features matter.

Are my sensitive documents uploaded to a remote compression server?

No. FreeToolsBox executes all stream optimization and image downsampling 100% locally in your web browser memory with complete privacy.

PDF Converters

PDF Compressor

Reduce PDF file size by compressing embedded images and optimizing document structures with zero server uploads.

🔒 100% In-Browser Compression: Bitmaps and PDF streams are compressed directly in browser memory. Zero files leave your computer.

PDF Target Document

Upload a PDF to get started

Choose a PDF up to 50 MB. Compression starts automatically.

Compression Space Savings

Upload a PDF to measure compression

Savings depend on the document. Pages are converted to images; selectable text, links and forms are not preserved.

Select Compression Level Preset

100% Private. Your data never leaves your device.

FreeToolsBox • Instant & Free

What is PDF Compressor?

Upload a PDF to compress it automatically in your browser. Each page is rendered as a JPEG image and rebuilt into a downloadable PDF. Choose Extreme, Recommended, or Low Compression and compare actual output sizes. Savings vary; text, links, and forms are rasterized rather than preserved.

Designed for accuracy, speed, and privacy, this tool runs entirely on your local device with zero network latency.

How to Use the PDF Compressor

1
Click Upload PDF and choose a PDF document up to 50 MB. Compression starts automatically.
2
Choose Extreme Compression, Recommended, or Low Compression to regenerate the output with different page image sizes and JPEG quality.
3
Wait for processing to finish. The Download Compressed PDF button enables only when the output is ready.
4
Review the reduction percentage and final file size before downloading your compressed PDF.

Formula & Calculation Logic

Renders each page using PDF.js, re-encodes the canvas as a JPEG, and embeds it in a new PDF using pdf-lib object streams. A smaller original document may produce a larger output.

Compression_Ratio = ((Original_Bytes - Compressed_Bytes) / Original_Bytes) * 100%

PDF Compressor Frequently Asked Questions

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