Compress PDF - Free Online Browser Tool

Optimize and reduce PDF size by compressing embedded raster graphics.

Most oversized PDFs are oversized for one reason: full-resolution scans and photographs embedded as images. This tool finds those embedded raster graphics and recompresses them at reduced resolution and quality, which is where the vast majority of the savings come from. Vector text is never touched, so the document stays sharp and searchable.

This compress pdf utility runs completely inside your web browser. Your document is opened locally and processed on your own device using JavaScript and WebAssembly, so your file is never uploaded to any server. There is no signup, no watermark and no limit on how many documents you can handle.

  • 100% client-side - files never leave your device
  • Instant processing, no upload wait
  • Works on desktop, tablet and mobile
  • Free forever, no account required

Common next steps: Eco Ink / Toner Saver, Convert to Grayscale (B&W), Merge PDFs, Flatten / Remove Annotations.

How to Use the Compress PDF Tool

Four steps, and the whole thing runs locally on your own device.

  1. Load the large PDF

    Drop in the file that is too big to email or upload. Its current size is shown so you have a baseline.

  2. Choose a compression level

    Pick mild, moderate or strong. Each level trades a little image fidelity for a meaningful reduction in file size.

  3. Compress the embedded images

    Embedded raster graphics are downsampled and re-encoded. Text, vector shapes and fonts are copied across untouched.

  4. Compare and download

    The result screen shows the before and after sizes and the percentage saved, then you download the compressed file.

Frequently Asked Questions

How much smaller will my PDF get?

It depends entirely on what is inside. A scan-heavy document often drops by 70–90%; a text-only PDF may barely change, because there is little raster data to compress.

Will my text still be selectable and searchable?

Yes. Text in a PDF is drawn as vector glyphs, not images, and this tool never rasterises it. Only embedded photographs and scans are recompressed.

How is this different from Ink Saver Mode?

Ink Saver targets print economy by flattening colour graphics to light monochrome. Compression targets file size by resampling images while keeping full colour.

What quality level should I choose?

Moderate is the sensible default. Strong is appropriate for documents that will only be read on screen, and mild when you plan to print at high quality.

Can compression ever make my file bigger?

Rarely, and only when the embedded images were already efficiently encoded at a low resolution. In that case the tool reports the file was left essentially unchanged.