PDF Compressor

The PDF Compressor re-renders every page of your document as a JPEG at a resolution you choose, which is why it shrinks scanned paperwork dramatically and text-only reports barely at all.

What is the PDF Compressor?

Most of a PDF's bulk is pictures rather than letters, so downsampling images is where nearly all real savings come from. This tool takes that principle to its conclusion: pdf.js draws each page at a resolution set by the quality slider, the canvas is encoded as a JPEG, and pdf-lib rebuilds a fresh document around those images. Quality 10 percent renders at 72 DPI with JPEG quality 0.30; quality 100 percent renders at 200 DPI with quality 0.92, and the default 80 percent sits near 174 DPI.

Key Features

• Quality slider maps to 72-200 DPI and JPEG quality 0.30-0.92
• Live size estimate samples your first three pages before you commit
• Page-one preview redraws as you drag, showing exactly what you lose
• Reports original size, compressed size, percent saved and compression ratio
• Runs on pdf.js and pdf-lib inside the page, with no upload

Common Use Cases

• Getting a scanned contract under a court portal's attachment size limit
• Shrinking a bundle of phone-scanned receipts before emailing an accountant
• Flattening a filled and signed form so its layout cannot shift
• Cutting a 300 DPI brochure scan down for a web download

How to Use the PDF Compressor

1. Drop a PDF onto the upload zone, or click it to browse for one.
2. Wait for the page-one preview and for Analyzing to resolve into an estimate.
3. Drag the quality slider and watch both the estimate and the preview change.
4. Press Compress PDF and let it work through the pages one at a time.
5. Compare the four result cards, then click Download Compressed PDF.

Tips for Best Results

• Scans and photo-heavy pages shrink hardest; a plain text report can come out larger than the original.
• Check the preview near 40 percent quality, because small print and thin rules blur before anything else.
• Keep the slider near 100 percent for anything destined for print, since that is where 200 DPI is reached.
• Save under a new name, because the flattened copy has no text layer left to recover.

Why Use WiserWork's PDF Compressor?

Compression is a trade, and this tool shows you the price before you pay it: the preview and the estimated size both update as you move the slider, so you can find the point where small print starts to smear. Nothing is uploaded, which matters when the file being squeezed is a signed contract or an identity document. The cost is real, though, since the output is a stack of pictures with no searchable, selectable or screen-readable text.

Who Uses the PDF Compressor?

It is used most by people pushing scanned paperwork through portals with hard attachment ceilings, from conveyancers to insurance claimants to anyone filing forms. Designers also reach for it to shrink a heavy proof for a quick review round. It is the wrong tool for anyone who needs the text layer to survive.

Frequently Asked Questions

Why did my PDF come out bigger than it started?

Because a text-only PDF stores letters as compact vector instructions, and this tool replaces them with pixels. Rasterizing a crisp text document at 174 DPI can easily produce more data than the original, which is why the toast says the file was already efficiently packed.

Can I still select or search the text afterwards?

No. Every page becomes a single JPEG, so text selection, copy, search and screen-reader access are gone. Keep the original file if any of that still matters.

What resolution does the quality slider actually produce?

It moves the render resolution linearly from 72 DPI at 10 percent to 200 DPI at 100 percent, and the JPEG quality from 0.30 to 0.92 alongside it. The 80 percent default works out to roughly 174 DPI at JPEG quality 0.80.

How reliable is the estimated size shown before compressing?

It renders up to the first three pages at your current setting, averages their encoded size, multiplies by the page count and adds about 3 KB of file overhead. It is close for documents whose pages are similar, and less accurate when one page is a photo and the rest are text.

Is my document uploaded anywhere?

No. The file is read with the browser's own file API and processed by pdf.js and pdf-lib in the page, so the bytes never leave your device.

Is there a maximum file size?

No cap is written into the tool. The real ceiling is memory, since every page is rendered to a full-size canvas, and a very long document on a phone can exhaust that before it finishes.

Does it handle password-protected PDFs?

Usually not. Encrypted files fail to open and you get a message saying the PDF could not be read, so remove the protection in the application that applied it first.

Will page size and orientation be preserved?

Yes. Each new page is created at the source page's exact point dimensions, and the image is drawn to fill it, so a mixed portrait and landscape document keeps its layout.

Do bookmarks, links and form fields survive?

No. Only the visible appearance is kept, so outlines, hyperlinks, annotations and fillable fields are all lost when the page becomes an image.

What setting should I use for a scan that will only be read on screen?

Somewhere between 60 and 80 percent is usually the sweet spot for screen reading. Watch the preview as you drag, since the point where body text stops looking clean depends on how small the original type was.

Compression here really means resolution: choose the lowest quality at which the preview still reads cleanly, confirm the estimate, and hold on to your original, because a flattened copy cannot be turned back into searchable text.