How to Reduce PDF File Size for Uploading or Emailing

Government portals, tax offices, banks, and web forms often cap attachment size at 1, 2, or 5 MB. Meanwhile a scanned contract or ID can easily weigh 10–20 MB. The good news: a PDF can almost always be compressed several times over without losing readability.

Why a PDF gets so heavy

It's almost always about the images. A text-only PDF spanning several pages typically weighs just tens of kilobytes. But a scanned or photographed document is essentially a high-resolution picture embedded in a PDF wrapper, and each scanned page can easily weigh 2–5 MB on its own. So compressing a PDF mostly means optimizing the images inside it.

How to compress a PDF online

The easiest approach is our PDF compressor: upload your file, choose a compression level, and download the smaller version. Processing happens on the server, nothing to install, and the file is deleted right after compression.

Three levels are available:

• Strong (72 dpi) — smallest file size, good for on-screen viewing and email. Images get noticeably less sharp, but text stays readable.
• Medium (150 dpi) — a balance between size and quality, suitable for most use cases.
• Light (300 dpi) — keeps quality as high as possible, good for printing.

If you need to hit a strict limit (say, "under 1 MB for the tax office"), start with strong compression and check the result.

What if compression doesn't help much

If the PDF barely contains any images to begin with, there isn't much to squeeze out, and the gain will be small. In that case, a different approach helps: if you actually need the document "as an image" (say, to send a single page), convert the PDF to images with PDF to JPG and send just the page you need as a separate file.

Tips

• Scan documents at a moderate resolution from the start (200–300 dpi is plenty for text).
• Avoid re-saving a PDF over and over — image quality degrades with each pass.
• Always double-check that text and stamps are still readable after compression before sending a document to an official body.

Compressing a PDF is the most common way to fit within upload limits. If you also need to edit the document, that's a different task — extracting text from a PDF.