How to compress a PDF
Drop a PDF on the tool above and press “Compress PDF”. The tool looks inside your file, shrinks any large JPEG photos it finds, strips the document's metadata, and re-saves the file. You get a download link for the smaller copy. Your original file is never changed, and nothing is uploaded — the whole job happens in your browser.
Why PDFs get big in the first place
Almost all PDF size comes from images. A scanned page is a full-page photo, often 300 DPI or more — far sharper than a screen can show. A ten-page scan can easily pass 20 MB, which is over most email attachment limits. Text, by contrast, is tiny: a hundred pages of plain text usually fit in a few hundred kilobytes. That is why compressing a PDF is mostly about shrinking its pictures, and why a text-only PDF barely shrinks at all.
What the settings do
The “largest image side” setting caps photo resolution. At 1500 px, a photo still looks sharp on screen and prints acceptably at small sizes. Drop to 800 px for files that only ever appear on screen, such as email attachments. The JPEG quality setting trades file size against photo detail: 0.65 is a good middle ground, 0.50 is visibly softer, and 0.80 keeps nearly all detail.
How much smaller will my file get?
Scanned and photo-heavy PDFs shrink the most — commonly 50–80% smaller. A text-only PDF might shrink by only 2–5%, because there is nothing to downsample. If your file barely shrinks, it was probably already efficient; try a lower image size or quality setting, or accept that the file is as small as it can honestly get.
What this tool does not do
It does not change your pages, fonts, or layout. Compression here means smaller images and a tidier file — not a different document. It also cannot open encrypted or damaged PDFs; remove the password first, or use an undamaged copy. And one hard limit: files over 50 MB are refused, because very large PDFs can run out of browser memory. Split a huge file first, compress the parts, and merge them back with the PDF Merger on this site.
When to use it
Use it before emailing, uploading, or submitting a PDF. Job applications, visa forms, university portals, and government sites commonly cap uploads at 2–10 MB. Compress first, check that the result still reads clearly, and then send the smaller file.