Compress PDF
Drop your PDF below. Choose how much to compress — Light, Balanced, or Strong.
Drop your files here
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Images, PDFs, Word docs, PowerPoints, audio, and more
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How OnlyFiles compresses PDFs
OnlyFiles uses Ghostscript, the industry-standard open-source PDF processor, to compress your files. Ghostscript re-renders the PDF at your chosen quality level — downsampling embedded images, optimizing font subsets, and removing redundant metadata. Light mode uses Ghostscript's "printer" preset, Balanced uses "ebook," and Strong uses "screen." Text and vector elements (lines, shapes, diagrams) are always preserved at full quality regardless of the compression level.
Understanding the three compression levels
Light compression is ideal for PDFs where image quality matters — reports, portfolios, and marketing materials. It typically reduces file size by 10–25% while keeping images sharp and readable. Balanced mode provides a middle ground, reducing size by 25–50% while maintaining acceptable quality — best for general business documents, newsletters, and archives. Strong compression prioritizes size reduction over visual fidelity, cutting files by 50–70% or more. Use Strong when the PDF is primarily for digital viewing on screens or when you need to meet strict size limits for email, storage, or uploads.
What gets preserved and what changes
Your PDF's text content is never altered — every word, every character, every font choice remains exactly as it was. Vector graphics like logos, diagrams, and line art stay crisp at any zoom level because they're resolution-independent. What changes are the embedded images: depending on your compression level, they're resampled to lower resolutions and re-encoded more efficiently. PDF metadata like titles, authors, and bookmarks are preserved. Annotations and form fields remain intact. The only thing stripped is redundant or bloated data that PDF exporters sometimes add.
When compression can't help
If your PDF is already optimized — for example, a text-only document or a file that's already been through compression — the output may not be smaller than the input. OnlyFiles detects this and returns your original file rather than giving you a "compressed" file that's actually larger. This is especially common with PDFs exported from modern tools like Google Docs or recent versions of Word, which already apply internal compression. Privacy note: Your PDF is processed on a secure server and deleted immediately after compression completes — we never store, log, or analyze your files.
When to use this
- Shrink a PDF to meet an email attachment size limit
- Reduce a scanned document for faster upload to a portal
- Compress a large report before sharing it with a team
Frequently asked questions
How do I reduce the file size of a PDF?
Drop your PDF at onlyfiles.org/compress/pdf and choose Light, Balanced, or Strong compression. Light keeps high quality, Strong gives maximum size reduction. If the file can't be compressed further, you get the original back.
What's the difference between Light, Balanced, and Strong compression?
Light compression reduces size while keeping near-original quality (best for documents with important images). Balanced is good for general use. Strong gives maximum compression — great for email attachments where small size matters most.
Will compressing a PDF reduce its quality?
It depends on the compression level. Light compression has minimal visible impact. Strong compression may reduce image quality within the PDF. Text and vector elements are always preserved perfectly.