How to compress a PDF under 5 MB without wrecking it

Almost every PDF that is too big is too big for the same reason: it is photographs of paper. A scanner or a phone produced a full colour image for every page, and a 12 page scan became 30 MB. The text inside a word processor export, by contrast, weighs almost nothing.

That tells you where the weight is, and therefore what to cut.

What to try, in order

1. Compress the images inside the PDF. This alone usually takes a scan from 30 MB to 3 MB.
2. Remove pages you do not need to send. A cover page nobody asked for is pure weight.
3. If the document came from a word processor, export it again as PDF rather than compressing the old file.
4. Only then reduce the resolution further, and check the smallest text is still readable.

Compress a PDF now

The number that matters is readability, not the percentage

Compression tools love to advertise ninety percent reductions. What matters is whether a person on the other end can read the account number. Zoom to one hundred percent, find the smallest text on the busiest page, and read it. If you can, you are done, whatever the percentage says.

When you cannot get under the limit

Some limits are simply below what a scan can be. When that happens, there are three honest ways out.

• Split the document and send it in parts, clearly named part one and part two.
• Scan again in grayscale at 200 dpi, which is the sweet spot for text documents.
• Ask whether they accept a link instead of an attachment. Many portals do and never mention it.

Why your phone scan is so heavy

Phone cameras shoot at twelve megapixels or more and the scanning app keeps all of it. A letter sized page at 200 dpi needs about two megapixels to be perfectly legible. The other ten are the file size.

Most scanning apps have a quality or document setting that does this for you. Set it once and every future scan will be small enough.

Common questions

Does compressing a PDF remove its text layer?

Not in a tool that compresses images. The text stays selectable and searchable. Tools that flatten a PDF to images do remove it, which also breaks accessibility, so avoid those for anything official.

Will a compressed PDF still print properly?

At 200 dpi and above, yes, for text documents. For anything with a photograph you intend to print at full page size, keep a higher quality copy for printing and send the compressed one.

Is it safe to use an online compressor for tax documents?

It is safe when the work happens in your browser and nothing is uploaded. Use the offline test from the merging guide: disconnect after the page loads and see whether it still works.