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How to make a PDF smaller before emailing it

Most email systems reject attachments above a size limit, and many forms cap uploads far lower. Before you reach for a random "compressor", it helps to know what actually makes a PDF large — because the fix depends on the cause.

First, find out why your PDF is large

A PDF is usually large for one of three reasons: it has many pages you do not need to send, its pages are high-resolution scans, or it embeds large images. A 40-page file where only 3 pages matter is a page problem, not a compression problem. A single scanned page at 600 DPI is a resolution problem. Knowing which one you have saves you from shrinking the wrong thing.

Method 1: Send only the pages you need

This is the fastest and safest win. If a form asks for one certificate page out of a 50-page file, extract just that page with the split tool and send only that. You keep full quality, you share less private information, and the file becomes a fraction of its old size in one step. Whenever the page count is the problem, this beats every other method.

Method 2: Re-scan at a sensible resolution

If you still have the paper original, re-scanning at 150–200 DPI in black-and-white or greyscale (for text documents) produces a far smaller file than a 600 DPI colour scan, and remains perfectly readable. This only applies when you control the scan. Do not re-photograph an already-scanned page with your phone camera — that usually makes quality worse without reliably reducing size.

Method 3: Re-save or print to PDF

Opening a PDF in a viewer and printing it to a new PDF sometimes drops unused data and embedded extras, giving a modest reduction. Treat this as a small bonus, not a solution: it rarely turns a 20 MB file into a 200 KB one, and it can strip links or form fields. Always check the new file opens correctly and nothing went missing.

What does not help

• Zipping the PDF: PDFs are usually already compressed inside, so a ZIP often saves almost nothing. It also forces the receiver to unzip first.
• Renaming or converting to another format and back: converting PDF to images and back to PDF normally makes the file larger and the text unsearchable.
• Screenshotting pages: phone screenshots are low-resolution, often skewed, and look unprofessional on a form.

An honest note about this site

This site's PDF tools merge and split; they do not re-compress images inside a PDF. If your file is large because of a few heavy scanned pages, extracting the pages you need (Method 1) is the tool here that helps most. For an image-heavy file where every page matters, re-scanning at lower resolution (Method 2) is the honest fix — no browser tool can invent quality that was never there, and any tool promising a 95% reduction on such a file is trading away readability.

Checklist before you hit send

• Open the final file and check every page is present and readable.
• Check the file size against the receiver's limit — email limits and form limits are different.
• Check you did not include private pages you meant to leave out.
• Give the file a clear name, like marksheet-page-3.pdf, not output.pdf.