Online Tool Store
PDF Compressor
Compress image-heavy PDF files for free with three quality levels. Everything runs privately in your browser, so your document is never uploaded.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Balanced - approximately 136 DPI
Best for scanned and image-heavy PDFs. Pages are flattened, so selectable text, links, forms, and layers will not remain interactive.
Loading the sample PDF - choose your own file to replace it.
How it works
- Choose a PDF and select the balance you want between image quality and file size.
- Each page is rendered locally at the selected resolution and encoded as a JPEG.
- The compressed page images are placed into a new PDF at the original page dimensions.
- Compare the sizes, then download the result without uploading either file.
The compression method
PDF size is reduced by lowering two costly parts of image-heavy documents: pixel resolution and JPEG encoding quality. The slider continuously maps 20-95% quality to approximately 72-168 DPI, so moving left reduces both resolution and JPEG quality while moving right keeps more detail. The sample above uses the same process as your own file.
Because pages are flattened, this method is intended for scanned documents, slide decks, and image-heavy PDFs. Use an optimizer that preserves document structure when selectable text, forms, links, layers, or accessibility tags are required.
FAQ
Is my PDF uploaded anywhere?
No. The PDF is read, rendered, compressed, and rebuilt inside your browser. Neither the original nor the compressed file is sent to Online Tool Store or another server.
How should I set the quality slider?
Start at 70% for a balanced result. Move left for a smaller file or right for sharper images and small text. The live label also shows the approximate rendering resolution.
Why did my PDF not get smaller?
PDFs that contain mostly text, vector artwork, or images that are already optimized may have little left to compress. When rebuilding would make a file larger, the compressor keeps the smaller original instead.
Will text and links stay selectable?
No. This compressor flattens each page into a quality-controlled image. The page remains visually readable, but selectable text, clickable links, form fields, layers, and accessibility tags are not preserved.
Can I compress a password-protected PDF?
Not directly. Remove the password with a trusted PDF application first, then choose the unlocked file here.
How we compare
| Feature | Online Tool Store | iLovePDF web | Smallpdf web |
|---|---|---|---|
| File never leaves your device | Yes - fully browser-based | No - uploaded for processing | No - uploaded for cloud processing |
| Fine-grained quality adjustment | Yes - 20-95% in 1% steps | Preset levels only | Preset levels only |
| No daily task limits | Yes - compress as often as needed | Free-plan processing limits | Free usage limits apply |
Choose Online Tool Store PDF Compressor for private, unlimited compression with precise quality control - your file stays on your device from start to finish.