How to Reduce PDF File Size for Email (Without Losing Readability)

Almost every email provider caps attachments at around 20–25 MB, and plenty of client portals are far stricter. When a scanned contract or an image-heavy report bounces back, the culprit is almost always the same: embedded images at full resolution.

Why PDFs get so large

A PDF is a container. Text is tiny — a 40-page text document might be under 1 MB. But the moment you add:

• Scanned pages (each page is really a photo),
• High-resolution product images, or
• Screenshots pasted at full size,

…the file balloons, because those images are stored at whatever resolution they came in at — often 300 DPI or higher, far more than a screen or standard printer needs.

The fastest fix: re-render at screen resolution

For most email purposes, 120 DPI is plenty and 96 DPI is fine for pure on-screen reading. Re-rendering each page at a sensible resolution and re-encoding the images as JPEG is what dedicated compressors do under the hood.

Our PDF Compressor does exactly this — in your browser. Pick a compression level, and each page is re-rendered and repacked locally. Because it never uploads your file, it's safe for contracts, medical forms, and anything confidential.

When to use each level

| Level | DPI | Best for | | --- | --- | --- | | Light | 150 | Keeping crisp text, modest savings | | Balanced | 120 | Emailing most documents | | Small | 96 | Scans that just need to be readable |

What about selectable text?

Rasterizing pages turns text into part of the page image, so it's no longer selectable. If you need searchable text preserved, keep the level light — or start from the original source file (a Word doc or design file) and export a fresh, optimized PDF instead of compressing a bloated one.

That "export from source" workflow is exactly the kind of thing worth automating if your team does it every week — which is where a small custom tool or assistant can save hours.