PDF Compressor

A PDF compressor reduces the file size of PDF documents while preserving their content and readability. Large PDF files are a common challenge: a scanned document, a presentation exported to PDF, or an image-heavy report can easily be tens of megabytes — exceeding email attachment limits, filling up shared drives, and slowing down document management systems.

PDF file size is largely determined by the images embedded within the file. Compressing these embedded images at a slightly lower quality can dramatically reduce file size with minimal visible impact on readability. Text in PDFs is vector-based and takes almost no space; it's the raster images (photographs, scanned pages, logos) that make PDFs large.

Altairys's PDF Compressor processes your document in the browser using pdf-lib — a client-side PDF manipulation library — to extract, compress, and re-embed images at your chosen quality level. The compression level slider lets you balance size reduction against quality. This tool is ideal for professionals submitting reports via email, students uploading assignments, and anyone managing document storage. Since all processing is local, your sensitive documents — contracts, financial reports, personal records — never leave your device.