PDF Compressor

Q: What if my PDF is password-protected?

Password-protected PDFs cannot be processed in the browser. Unlock the file first, then compress it here.

Reduce your PDF file size online for free. Everything runs right in your browser — your file is never uploaded anywhere. Free, private, no signup.

Honest expectations: results depend on your PDF. Text-only PDFs barely shrink (there is little to remove), while photo-heavy PDFs can shrink a lot. This free tool runs entirely in your browser — it cannot match server-grade compressors on every file. Your file never leaves your device.

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Drag & drop your PDF here, or click to browse
Max 50 MB · PDF files only

Compression level

LightRemoves hidden metadata and rebuilds the file structure. Fastest, 100% safe, no visible change. Best for text PDFs. MediumEverything in Light, plus shrinks large photos to 1600px at balanced quality. Best all-rounder for mixed PDFs. StrongAggressive photo compression (1000px, lower quality). Smallest files — fine for screen viewing, not for print.

How to use

Drop a PDF into the box above (or click to browse). Files stay on your device — nothing is uploaded.
Pick a compression level: Light for text documents, Medium for everyday files with photos, Strong when you need the smallest possible file.
Click Compress PDF and watch the progress. The tool strips hidden metadata, rebuilds the file structure, and (on Medium/Strong) re-encodes large photos.
Compare the before/after sizes, then hit Download. If the result barely shrank, your PDF was probably already optimized — try Strong, or accept that text PDFs have little to give.

About this tool

This compressor is built on pdf-lib, a well-known open-source PDF library, running 100% in your browser via JavaScript. On Light it removes hidden document metadata and re-saves the file with compressed object streams. On Medium and Strong it additionally finds embedded JPEG photos and re-encodes them smaller — each image is validated before use, and any image that cannot be safely processed is skipped rather than risking a broken file. The finished PDF is re-opened and verified before the download button appears, so you never receive a corrupt file.

Frequently Asked Questions

Is my PDF uploaded anywhere?

No. The entire compression happens in your browser with JavaScript. Your file never leaves your device, so it is safe for contracts, resumes, and private documents.

Why didn't my file shrink much?

Text-based PDFs are already compact — there is simply little to remove. The biggest savings come from PDFs full of large photos. If Light barely helped, try Medium or Strong; if the file was already optimized, even those may only shave off a few percent.

Will compression reduce quality?

Light never touches visible content — only hidden metadata and file structure. Medium slightly reduces large photos (usually unnoticeable on screen). Strong visibly softens photos when zoomed in, so keep your original if you need print quality.

What is the maximum file size?

50 MB. Browsers have limited memory, and very large PDFs can freeze the tab. For bigger files, a desktop tool is the safer choice.

What if my PDF is password-protected?

Password-protected (encrypted) PDFs cannot be processed in the browser. Unlock the file first with your PDF reader, save an unprotected copy, then compress it here.

ToolsHacks PDF Compressor — free, private, and client-side. Part of the ToolsHacks free online tools collection.