PDF Compressor
Reduce PDF file size without losing quality. Three compression levels. Runs in your browser — no upload, free.
Drop PDF here or click to browse
Supports PDF files
About PDF Compressor
Large PDF files cause problems across the board: email systems reject attachments over a few megabytes, government and HR portals cap upload sizes, and sharing via messaging apps compresses images and degrades quality. The PDF Compressor reduces file size losslessly — it strips the document metadata and repacks the file's internal objects into compressed object streams. Nothing is ever re-encoded, so text, vector graphics and images come out exactly as sharp as they went in.
The tool offers three levels. Low rewrites the file without object streams and removes nothing — the most conservative option, for when you want the document left as close to untouched as possible. Medium, the recommended default, clears the document info metadata (author, creator, producer, subject, title, keywords) and packs the objects into compressed streams. High does everything Medium does and additionally drops the XMP metadata packet, which is often several kilobytes of embedded XML that carries no visible content.
How much you save depends entirely on what is inside the file. PDFs generated by word processors and design tools carry a lot of metadata and loose objects, and typically shrink 10–40%. Files whose bulk is scanned image data barely move, because that image data is already compressed and is never touched here. All processing runs locally in your browser using pdf-lib, which matters for sensitive documents: scanned passports, medical records, financial statements, legal contracts — all stay on your device. You see exactly how much space was saved before downloading the result.
How to Use PDF Compressor
- 1Drop your PDF into the upload area, or click it to browse — the file name and page count appear once it loads.
- 2Select the compression level — Low, Medium or High. Medium is recommended for most documents.
- 3Click "Compress PDF" and wait for the browser to process the document locally.
- 4Review the before/after comparison, which shows both sizes and the percentage saved.
- 5Click "Download Compressed PDF" to save the result to your device.
- 6If the file was already optimised, the tool says so instead of pretending it saved space.
Use Cases
- →Shrink a text-heavy PDF to meet an email attachment size limit (typically 10–25 MB)
- →Strip author, title and producer metadata from a document before sending it outside your company
- →Reduce a PDF portfolio or presentation for faster web download and sharing
- →Trim exported reports and invoices to reduce storage costs in a file management system
- →Remove the XMP metadata packet that design and export tools embed in generated PDFs
- →Prepare PDF submissions for online application portals with strict file size limits
Tips
- ✓Medium is the best starting point — it handles most documents well
- ✓Compression here is lossless: no image is ever re-encoded, so the output looks identical to the original
- ✓Scanned, image-only PDFs shrink the least — their bulk is image data that is already compressed
- ✓If the result is still too large, split the PDF into smaller parts with our PDF Tools instead
- ✓Use Low or Medium for PDF/A files — High removes the XMP packet, which breaks PDF/A conformance
- ✓Medium and High clear the document metadata, so keep the original if you need the author and title fields
- ✓A file that reports no reduction is simply already optimised — there was nothing left to strip
- ✓Password-protected PDFs cannot be opened for compression; remove the password first
Frequently Asked Questions
The compressor rewrites the PDF with pdf-lib: it strips document metadata and packs the file's internal objects into compressed object streams. Nothing is re-encoded, so text, vector graphics and images keep their original quality — the compression is lossless.
Low: rewrites the file without object streams — the most conservative option. Medium (recommended): removes document metadata such as author, title and producer, and enables compressed object streams. High: everything Medium does, plus dropping the XMP metadata packet. Image quality is identical at every level.
No. All compression happens entirely in your browser using PDF-lib. Your file never leaves your device.
Some PDFs are already optimised: they carry no metadata to strip and their objects are packed in streams already, so there is nothing left to remove. Scanned, image-only PDFs also change very little, because their bulk is image data that is already compressed and is never re-encoded here.
Password-protected PDFs cannot be processed — you will see an error. Standard PDFs work fine. For PDF/A files, use Low or Medium: the High level removes the XMP metadata packet, which breaks PDF/A conformance.
There is no enforced limit — the tool is bounded only by your browser memory. For most documents (under 100 MB), compression completes in a few seconds.