Why PDFs get large
Most oversized PDFs are heavy because of images — high-resolution photos or scanned pages stored at full quality. Embedded fonts, multiple layers, and metadata add to it, but images are usually 90% of the weight. That is why a text-only PDF is tiny while a scanned booklet can be tens of megabytes.
How PDF compression works
A compressor re-encodes the images inside the PDF at a lower resolution or higher compression ratio, and strips redundant data. Text stays as text (vector), so it remains sharp; only the images are reduced. The art is lowering image weight enough to hit your target size while keeping pages legible.
Step by step
Open a compress tool, choose your PDF, pick a compression level if offered, and download the smaller file. Check the result at 100% zoom — if photos look fine and text is crisp, you are done. If it is still too big, compress harder or split the document and send it in parts.
How small can you safely go?
For documents that are mostly text, aggressive compression is safe. For photo-heavy or print-bound files, go gentler — over-compression makes images blocky and small text fuzzy. Aim for the largest size that still meets your limit rather than the smallest possible file.
When compression is not the answer
If a PDF is large because it has hundreds of pages, splitting it is better than crushing the images. If you only need a few pages, extract them instead. And if you need the original print quality, send via a link rather than email.