How to Reduce PDF Size for Email and Online Form Upload

Updated 2026-10-26 · 3 min read

Scanned documents and phone scans are often much larger than they need to be. Portals may allow only 1 MB or 2 MB per file, and email attachments also have limits.

The Compress PDF tool shrinks image-heavy and scanned PDFs by re-drawing each page at a lower resolution. It runs on your device, so your documents are not uploaded.

Compress your PDF now — Compress PDF

Step by step

  1. Choose your PDF Drop the PDF into the box or click to choose it.
  2. Pick a compression level Choose 'Smallest file (72 DPI)', 'Balanced (108 DPI)' or 'Better quality (144 DPI)'. Balanced is a good start for most scans.
  3. Compress Press Compress. A progress bar shows the pages being processed.
  4. Compare and download The tool shows the original size, the new size and the change in percent. If it is smaller, press Download. If the limit is still not met, try 'Smallest file'.
  5. Many PDFs? Use bulk Switch to 'Many files (bulk)', choose the level once, add all the files and press Compress all. You can download them as a ZIP.

Important: what changes in the compressed PDF

Each page is turned into a JPEG image. This makes scanned PDFs much smaller, but the text can no longer be selected, copied or searched. For a PDF made from Word or a website (with real text), the result can even be larger. The tool tells you when this happens, and you should then keep the original.

Always keep your original file.

Which level to choose

LevelBest for
Smallest file (72 DPI)Strict limits like 1 MB; fine for reading on screen
Balanced (108 DPI)Most scanned forms and certificates
Better quality (144 DPI)Small print, or documents that may be printed

Other ways to make the file smaller

  • Remove pages the portal does not need before compressing.
  • Scan in black and white or greyscale if colour is not required.
  • If the PDF is password-protected, remove the password first with Unlock PDF (you need to know it).
  • If the PDF was made from photos, compressing the photos before turning them into a PDF also works well.

Common upload limits to keep in mind

Limits differ from site to site, so always read the instructions on the portal. Many job, exam and admission portals allow a few hundred KB to 2 MB per document. Email services commonly allow attachments of around 20 to 25 MB, but a smaller file is easier for the receiver to open on a phone.

A good habit is to aim a little below the limit. For a 1 MB limit, a 900 KB file is safer than one of exactly 1 MB.

Common mistakes

  • Compressing the same file again and again. Each round makes it blurrier. Go back to the original and choose a stronger level instead.
  • Not checking the result. Zoom in on small print, signatures and stamps before you upload.
  • Compressing a PDF that must stay searchable, like a contract you will copy text from. Keep that one as it is.

Questions

Why is my compressed PDF bigger than the original?

Your PDF probably has real text rather than scanned images, so it is already efficient. Keep the original, or remove pages you do not need.

Can I compress a PDF to under 1 MB?

Often yes for scans. Try Smallest file. A long document with many pages may still be over 1 MB; then split it or remove pages.

Will the text still be readable?

Yes, it will look the same on screen at normal zoom, but you will not be able to select or search the text.

Is my PDF uploaded?

No. Compression happens in your browser and the file never leaves your device.

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