Compress PDF

Large PDF files create friction at every step, email clients reject them, cloud storage fills up, portals time out during upload, and mobile data gets consumed loading them. The primary cause of PDF bloat is embedded high-resolution images from scanned documents and exported reports. Compressing a PDF reduces the resolution and quality of those embedded images, shrinking the overall file size while keeping the text and document structure fully intact and readable. This tool compresses PDF files locally on your device using pdf-lib, your documents never leave your device.

How to use

1. Open your PDF. Drag the file onto the drop zone or click to browse. The original file size is shown immediately so you have a baseline to compare against after compression.
2. Choose a compression level. Select from Low, Medium, or High compression. Low reduces size modestly while preserving maximum quality. High produces the smallest file at the cost of image quality, appropriate for documents where readability matters more than image fidelity.
3. Compress and review. The compression runs locally and completes quickly. The new file size and percentage reduction are shown before you download.
4. Download the compressed PDF. Click Download to save the reduced file. The document structure, text, links, and layout remain intact, only the embedded images are resampled.

Tips for best results

• Compress after merging. If you're combining multiple PDFs, merge them first and then compress the combined file. Compressing individual files before merging and then merging the results tends to produce a larger output than merging first.
• Use Medium for most documents. The Medium compression level strikes the right balance for most use cases, email attachments, portal uploads, and shared reports all benefit without visible quality degradation on screen or print.
• Use High only for archival or preview. High compression noticeably reduces image quality. Use it when a document is for quick reference rather than final delivery, or when you need to meet a hard file size cap on an upload form.
• Text-only PDFs won't compress much. If your PDF contains no images, just text and vector graphics, compression will have minimal effect because text is already stored very efficiently in the PDF structure.

Why use PixMidas

• 100% private. PDF compression runs entirely on your device. Your documents are never uploaded to any server, particularly important for contracts, invoices, medical records, and personal documents.
• Multiple compression levels. Choose Low, Medium, or High to match the trade-off between file size and image quality that your use case requires.
• No account needed. Free and instant. Compression runs locally on your device.

Frequently asked questions

What does PDF compression actually change?

This compressor primarily reduces the resolution and quality of images embedded in the PDF. It does not change, remove, or re-render text, vectors, fonts, form fields, or document structure. The result is a visually similar document where text and layout remain crisp, but photographs, scanned pages, and background images are displayed at lower resolution.

Why didn't my PDF shrink much?

PDF files that consist mainly of text, vector graphics, and font data have very little image data to compress. Scanned documents (which are essentially images of pages) compress dramatically. Word processor PDFs with some images compress moderately. If your file didn't shrink significantly, it likely contains little image content to optimize. If you need to reduce a text-heavy PDF further, removing embedded fonts or subset fonts, a more advanced PDF operation, would be required.

Will compression affect my PDF's text readability?

No. Text in PDFs is stored as vector outlines or font glyphs, not as pixel images. Compression only affects raster image data embedded in the PDF. Text remains perfectly sharp regardless of the compression level chosen. Scanned documents are an exception, a scanned page is entirely an image, so the entire page is affected by image compression.

Can I compress password-protected PDFs?

No. The tool cannot read or process password-protected PDF files. Remove the password protection first using Adobe Acrobat, Preview on Mac, or a similar tool, then compress the unprotected version. After compression, you can re-apply password protection if needed using a PDF editor.

How does this compare to sending a PDF via email compression?

Email clients do not compress PDF attachments, they're transmitted at their original size. If a recipient's inbox or your outbox has a size limit, you need to reduce the PDF size before attaching it. Many email services have a 10 MB or 25 MB attachment limit. After compressing here, your document should pass most standard email attachment restrictions.

Should I compress before or after merging PDFs?

Compress after merging. If you merge multiple PDFs first and then compress the combined file once, you get better results than compressing each file separately before merging. This is because the compressor can optimize the entire document in one pass rather than working on fragments that then get reassembled.