Compress PDF Online

Reduce PDF file size online with smart compression modes, custom quality settings, image downsampling, and grayscale conversion when needed.

Why compress PDF files?

  • Reduce PDF size before sending documents by email

  • Meet file size limits for uploads, forms, and portals

  • Make scanned PDFs easier to share and store

  • Optimize reports, presentations, and brochures for web delivery

  • Shrink image-heavy PDFs without recreating the document

  • Keep readable quality while making files lighter

How to compress PDF files in 3 steps

Upload your PDF
Drag and drop your PDF file or choose it from your device.
Choose compression settings
Select an automatic mode or configure quality, grayscale, DPI, and optimization settings manually.
Download the smaller PDF
Start compression and save the optimized PDF file to your device.

What you can do with the PDF compressor

Choose a compression mode

Use smart automatic compression or switch to low, medium, high, or custom mode depending on whether you need the smallest file or better visual quality.

Use ready-made quality profiles

Pick preset profiles such as screen, ebook, printer, or prepress to match common PDF optimization scenarios without manual tuning.

Control image quality

Adjust JPEG quality and image recompression behavior to reduce file size while keeping text and embedded images usable.

Downsample high-DPI images

Set DPI thresholds and target DPI values to compress oversized scanned pages and image-heavy PDFs more efficiently.

Convert to grayscale

Remove color when it is not needed. Grayscale conversion often reduces file size for scans, drafts, and internal documents.

Keep the original if it is smaller

Avoid getting a worse result. If compression is not beneficial, the tool can keep the original PDF instead of replacing it.

Who uses PDF compression?

Office and admin teams

Compress contracts, invoices, forms, and internal documents before sending them by email or uploading them to business systems.

Students and teachers

Reduce the size of assignments, scanned notes, and course materials so they are easier to submit and share.

Legal and compliance teams

Optimize large case files, supporting scans, and archived documents while keeping them manageable for portals and record systems.

Design and marketing teams

Make brochures, presentations, and review PDFs lighter for client delivery, approvals, and online distribution.

Finance departments

Shrink statement packs, receipt bundles, and exported reports to simplify storage and transmission.

Anyone working with scanned PDFs

Reduce oversized scan files produced by office scanners, multifunction printers, and mobile scanning apps.

Why choose us

We ensure quality, convenience, and support for all formats.

High-quality conversion
High-quality conversion
We guarantee precise file conversion without any loss of quality.
Support for multiple formats
Support for multiple formats
You can convert your files from over 200 different formats, including images, documents, and more.
Compatible with all devices
Compatible with all devices
Convert files from any device – whether it's a computer, tablet, or smartphone.
User-friendly interface
User-friendly interface
Our service is designed to make conversion easy for everyone in just a few simple steps.
Full data security
Full data security
All files are transmitted and stored using advanced encryption technologies.
High-speed processing
High-speed processing
Thanks to cloud technology, we ensure fast processing even for large files.

Frequently Asked Questions

The final reduction depends on the document. Scanned and image-heavy PDFs usually shrink more than text-only PDFs that are already optimized.

Use Auto for a balanced result, Low for the smallest files, Medium for everyday use, High when you want to preserve more quality, and Custom when you need manual control.

It can, especially when images are recompressed or downsampled aggressively. Higher quality settings preserve more detail but usually produce larger files.

It converts the document from color to grayscale. This often reduces file size when color information is not important.

The threshold defines which embedded images are considered too large and should be recompressed. The target DPI defines the resolution they should be reduced to.

If you enable the keep-original option, the tool keeps the source PDF instead of returning a larger processed file.

Yes, if you know the password. The tool can process protected PDFs when the correct password is provided.

About PDF Compression

What PDF compression does

PDF compression reduces the size of a document so it is easier to send, upload, store, and load. This is especially useful for scanned files, image-heavy reports, presentations, brochures, and exported documents that would otherwise be too large for email attachments or upload limits.

An online PDF compressor handles this directly in the browser workflow. Instead of reopening the document in desktop software, exporting again, or rebuilding the file from scratch, you can upload the PDF, apply compression, and download a smaller version in a few steps.

Why some PDFs shrink more than others

Not every PDF compresses the same way. A text-only PDF generated from a word processor may already be compact and leave little room for further reduction. In contrast, scanned PDFs and documents with large embedded images often contain much more data than necessary for everyday viewing and sharing.

This is why compression results vary. The biggest reductions usually come from recompressing images, lowering image resolution, converting color pages to grayscale, and cleaning up unnecessary internal PDF data.

Smart presets and custom control

For quick optimization, preset compression modes are useful because they balance quality and file size automatically. Modes like low, medium, and high make it easy to choose between stronger compression and better visual fidelity without dealing with technical parameters.

Custom mode is more useful when the document has specific requirements. You can choose a quality setup method, use preset output profiles such as screen, ebook, printer, or prepress, or adjust numeric and advanced settings for more precise control.

Image quality, DPI, and grayscale

Most PDF size reduction comes from images. Lower JPEG quality reduces file size by applying stronger compression to embedded images. DPI settings affect how much image resolution is preserved, which matters most for scans, photos, and graphics inside the document.

Downsampling high-DPI images can dramatically reduce file size when the source PDF contains oversized scans. Grayscale conversion can reduce size further when color is not essential, for example in text documents, office scans, or internal drafts.

When to use keep-original protection

Some PDFs are already optimized, and processing them again may not produce a smaller result. In those cases, a keep-original option is useful because it prevents the compressed output from becoming larger than the source file.

That makes compression safer for routine workflows. You can try optimization without worrying that the final download will be less efficient than the document you started with.