pdfpix

Compress PDF to 3 MB

or drop one here
Compression level
Target size
Choose a PDF file first.

3 MB is 3,145,728 bytes. It is the cap on a lot of application portals, and it is the practical size for emailing a document that has to stay readable. The bench did not run a 3 MB target, so nothing here quotes a measured hit rate for it.

How to compress a PDF to 3 MB

  1. Choose the PDF

    Press Choose a PDF, or drop the file on the page. The file is read in this tab and is not sent anywhere.

  2. The target is already set

    This page opens at 3 MB, so there is nothing to type. Pick a different level, or enter your own smaller number in KB, if you want another size.

  3. Press Compress

    Four methods race: copy the pages into a fresh file, re-encode the placed images, cut each embedded font down to the glyphs the pages draw, and, only when no other method reached the target, redraw the pages as images with the text kept on top.

  4. Read the check, then download

    Every candidate is opened again and its characters are counted against the source. The page shows the size, the method that won and the characters kept before it offers the download.

The four methods are described in full, with the measurements behind them, in how it works.

A colour scan against a text export

The same page count behaves completely differently at 3 MB depending on what the pages are. A forty page text export usually arrives under 3 MB before compression even starts. A forty page colour scan starts at twenty or thirty megabytes and has to give up most of it.

That is the split the published run measured. Scans met their target on 16 of 18 cases, because image quality is a dial with a long travel. Text documents managed 10 of 50, because fonts and structure do not compress the same way.

What a 3 MB budget buys per page

Twenty pages at 3 MB is 150 KB of image each, which is a good scan. Fifty pages is 60 KB each, which holds printed text and softens small type. A hundred pages is 30 KB each, which is where a scan stops being pleasant to read.

The compress tool reports the quality it settled on, so you can see where in that range you landed without opening every page. Check the page with the smallest type before you send the file.

Around the 3 MB mark

If the cap is mail rather than a portal, remember the encoding overhead. Mail inflates attachments by roughly a third, so a hard 3 MB mail limit wants a PDF near 2.2 MB. A 2 MB target clears that without argument.

If the cap is generous, a 4 MB target buys a third more image detail for the same effort. The large file guide covers the case where the source is far bigger than any of these numbers. The tool is free, and it will reduce the file only as far as the target you name.

Questions

Is 3 MB enough for a fifty page scan?
It works out to about 60 KB per page, which holds printed body text and softens small print. Readable, not comfortable. If the pages carry footnotes or handwriting, a larger target or a split file is the better call.
How many bytes is a 3 MB limit?
3,145,728 bytes in binary units, which is what this tool uses. A portal counting in flat millions stops at 3,000,000, a gap of about 146 KB. Target 2.9 MB if you have already been refused once.
Why is my text document already under 3 MB?
Because text weighs very little. A page of text is a few kilobytes of drawing instructions plus a share of the embedded fonts. Documents only get big when they carry images, and a text export usually does not.
Does a 3 MB target touch the images at all?
Only if the two lossless methods fall short. The structural rebuild and the font subset run first and change nothing visible. The result names the winning method, so you know whether any pixel was re-encoded.

The other pdfpix tools

All 30 of them run in a browser tab like this one. Each reads its own output back and checks it before offering the download, and none of them needs an account.

Where to go next