Compress PDF Online Free — Reduce File Size up to 90%

PDFs grow large mainly due to embedded high-resolution images. Our compressor reduces image resolution and applies JPEG compression while keeping text sharp. For more control, try our PDF optimizer to strip metadata, flatten forms, and linearize for web.

Typical reduction is 30–80% depending on image content. The Maximum preset can achieve 60–90% reduction on image-heavy PDFs. Text-heavy PDFs compress less.

No. Text in PDFs is vector-based and is not affected by compression. Only embedded images are re-sampled. You can see the DPI and quality settings before compressing.

This preset uses 100 DPI and 50% JPEG quality with automatic metadata stripping and web optimization — ideal for getting PDFs under typical email attachment limits (10–25 MB).

Custom mode lets you precisely control image DPI (36–300) and JPEG quality (10–100%). Lower DPI and quality = smaller file. You can also enable grayscale, strip metadata, remove annotations, or linearize for web.

Linearization rearranges the PDF so browsers can display the first page before the entire file downloads. Ideal for PDFs served on websites.

This means the file is already well-compressed and can't be reduced further with the current settings. Try the Maximum preset, enable Remove all images, or use Custom mode with lower DPI.

Yes. All 5 compression presets (Maximum, Balanced, Quality, Email, Custom) and all advanced options are completely free. Unlike Smallpdf or Adobe, there are no locked 'Pro' compression levels.

Yes. Your file is uploaded securely, compressed on our server using Ghostscript, and automatically deleted within 1 hour. Files are never stored long-term or shared with third parties.

Yes. Scanned PDFs are typically image-heavy and benefit the most from compression. The Maximum preset can reduce scanned PDFs by 60-90%. Use Custom mode to fine-tune DPI for the best quality-size tradeoff.

DPI (dots per inch) controls image resolution — lower DPI means smaller, lower-resolution images. JPEG quality controls the compression strength applied to each image — lower quality means more compression artifacts but smaller size. Adjusting both gives you precise control.

The tool doesn't target an exact file size, but you can use Custom mode to adjust DPI and JPEG quality until you reach your target. Start with a lower DPI (72-100) and quality (30-50%) for maximum reduction, then increase if the result is too blurry.

Six advanced options: convert to grayscale (removes color for smaller files), strip metadata (author, dates, GPS), web-optimize/linearize (faster browser display), flatten forms (static content), remove annotations (comments, highlights), and remove all images (text-only output).

Yes. Compress PDF runs entirely in your browser using WebAssembly. Your files are never uploaded to any server — they stay on your device throughout the entire process. No data is transmitted, stored, or accessible to WhiskFile or any third party.

Yes. Compress PDF works on any device with a modern browser — iPhone, Android, iPad, tablets, Chromebooks, and desktop computers. No app download required. The interface adapts to your screen size automatically.

Compress PDF accepts PDF files as input and produces PDF output. The maximum file size is 50 MB on the free plan (500 MB for Pro users). There are no page count limits.