How to make a PDF smaller for email without uploading it
· 6 min read
Open the Compress PDF tool, load the file, pick a level and download compressed-<yourfile>.pdf. The tool shows the new size and the percentage saved, so you know straight away whether it fits under your email limit. One thing to know before you send it: the browser tool redraws every page as a JPEG image and builds a new PDF from those images, so the pages look the same but the text in the result is no longer selectable or searchable.
TL;DR: three levels (extreme, recommended, less). Scans and photo-heavy files shrink a lot; a text-only PDF may not shrink at all and can even grow. Keep the original, because the compressed copy has lost its text layer. Everything runs in your browser tab, nothing is uploaded.
What size does an email attachment have to be?
It depends on the sender and the receiver, so check both. Gmail's help page says personal accounts have a 25 MB attachment limit and that Gmail turns larger attachments into a Google Drive link, while work and school accounts can have different limits set by an administrator. Other providers and company mail servers set their own caps, and a recipient's server can reject a message your own provider accepted. If a message bounces, the number in the bounce text is the one to aim under.
Open the Compress PDF tool: load the file, pick a level, download the smaller copy.
Which compression level should I pick?
Start with recommended and look at the size the tool reports. Only go to extreme if it is still too big, and only go to less if the result looks soft. The levels differ in two settings, the pixel size each page is drawn at and the JPEG quality it is saved with.
| Level | Page drawn at | JPEG quality | Pick it when |
|---|---|---|---|
| Extreme | 1x (72 pixels per inch) | 0.5 | The file must get under a hard cap and you accept softer images |
| Recommended | 1.5x (108 pixels per inch) | 0.7 | You want a smaller file that still reads well on screen |
| Less | 2x (144 pixels per inch) | 0.9 | Quality matters more than the last megabyte |
The pixel-per-inch figures are the drawing scale times 72, the number of PDF points in an inch. The tool has no target size box and no way to say make this 5 MB, so getting under a cap is a matter of trying a level and checking the result.
Why is my text no longer selectable after compressing?
Because each page was rendered to a picture. That is how the size drops on scans and photo pages, and it is also why the text layer disappears: what is left is an image of the page, the same as a scan. You cannot copy text from the result, search it, or use a screen reader on it. Links on the pages stop working for the same reason.
That makes the copy fine for sending a contract to be read or signed on paper, and a poor choice for a file someone needs to search or copy from. Always keep the original next to it. If the recipient needs the text, send the original in pieces instead, as described below.
Why did my file get bigger, or barely shrink?
A PDF made from a word processor is mostly text and fonts, which are already very compact. Redrawing its pages as images can produce a file about the same size, or larger. The tool does not stop you in that case, it simply reports the result, so compare the two sizes before you attach it. Compression pays off on scans and pages full of photos, where images are most of the weight.
What can I do instead of compressing?
- Remove pages nobody needs first, with the Split PDF tool, then compress the shorter file if it is still too big.
- Send a text-heavy file in two or three parts. Each part made with Split PDF keeps its text, and the recipient can join them with Merge PDF.
- Share a link to the file in cloud storage instead of attaching it, if the recipient does not need an attachment.
- For photos in a PDF, shrink the photos before building it, then use JPG to PDF.
What should I check before I attach it?
- Size: the tool reports the new size. Make sure it is under the limit with some room to spare.
- Legibility: open the result and zoom in on the page that matters most, such as a signature, a stamp or a table.
- Page count: it should match the original.
- Name: the download is called compressed- followed by the original file name. Rename it if the original name contains something private.
See also: compressing a PDF without wrecking it: why results vary so much between a scan and a text file.
See also: how to delete pages from a PDF: drop the pages you do not need before you compress.
Frequently asked questions
How do I make a PDF smaller for email?
Open the Compress PDF tool, load the file, choose extreme, recommended or less, and download the result. The tool shows the new size and the percentage saved, so you can try another level if it is still too big.
Is the text still selectable after compressing a PDF on AstralPDF?
No. The browser tool redraws each page as a JPEG image and builds a new PDF from the images, so the text is no longer selectable or searchable. Keep the original if you need the text.
Why is my compressed PDF the same size or bigger?
A PDF that is mostly text and fonts is already compact, and redrawing its pages as images can give a file of similar size or larger. Compression helps most on scans and photo-heavy files.
Can I choose a target size like 5 MB?
No. There are three levels and no target size option. Try a level, check the size the tool reports, and try another if needed.
Is my PDF uploaded when I compress it?
No. The compression runs in your browser tab and the finished file is saved straight from the tab. The original on your device is not changed.