How to Compress a PDF Without Losing Quality (Free)

You need to email a PDF and it's over the 10 MB attachment limit — or a portal insists on "max 2 MB" for a 14 MB scan. The fix is compression, and done right it's barely visible. Here's how PDF compression actually works, and how to do it free without uploading your document anywhere.

Why PDFs get huge in the first place

Text in a PDF is tiny. The bulk almost always comes from images — scans, photos, and screenshots embedded at print resolution. A 300-DPI scanned page can be 2–5 MB on its own; ten pages later you have a monster file. That's why compression focuses on re-encoding the imagery, not the text.

The quality trade-off, explained

Compressing a PDF re-renders its pages and saves the images at a lower quality setting. The sweet spots:

• High quality — visually indistinguishable for most documents; expect 40–60% smaller. Right choice for contracts and anything with fine print.
• Medium — small artifacts if you zoom in; 60–80% smaller. The everyday email setting.
• Low — visible softness, maximum shrinkage. For "must be under 1 MB" portals where legibility just needs to survive.

One caveat worth knowing: heavy compression rasterizes pages, which can make text non-selectable. If you need the text layer later, grab it first with Extract Text from PDF.

Compress it free — without uploading

Most compression sites send your document to their servers. Ours doesn't: Compress PDF runs entirely in your browser, shows you the before/after size live, and lets you pick the quality level. Your contract, medical record, or ID scan never leaves your device.

Getting under a specific limit

• Under 2 MB: start at Medium; drop to Low only if needed.
• Under 1 MB: Low quality — and consider splitting the document first with Split PDF so you only send the pages that matter.
• Multiple files: merge them with Merge PDF before compressing, so one pass handles everything.

Scans: fix them before you shrink them

If your scan is sideways, straighten it with Rotate PDF before compressing. And if you're building a PDF from photos, downsize the images first with the Image Compressor, then combine them via Images to PDF — you'll get a dramatically smaller result than compressing after the fact.

Bottom line

Compression is an image-quality dial, not magic. Pick the highest quality that fits your size limit, keep sensitive files in-browser, and split before you squash when a hard cap looms.