How to Compress a PDF Online for Free — No Upload Required

Our tool offers three compression levels to match how you plan to use the file.

Print quality preserves images at 200–300 DPI. This keeps photos and graphics sharp enough for printing but still reduces file size by 20–40% compared to uncompressed scans. Use this for archival copies or documents that may need to be printed later.

Screen quality (default) drops images to 150 DPI. Text remains crisp, photos lose some fine detail, and file sizes shrink by 40–70%. Best for sharing documents that will mainly be viewed on monitors, tablets, or phones.

Email-ready compresses aggressively at around 100 DPI. Photos will look soft on close inspection, but charts, text, and diagrams stay clear. This preset typically delivers 60–80% size reduction — ideal for squeezing an oversized PDF past email attachment limits.

If you are unsure, start with screen quality. It works well for 90% of use cases and still gives significant size savings.

Three scenarios produce disappointing compression results.

Already-compressed PDFs: If your PDF was exported from Google Docs, Word, or Save as PDF from a browser, it is likely already compressed. Running it through our tool again usually saves only 5–15% — not the 40–80% you might expect. This is normal, not a bug. The file was already efficient.

Vector-only PDFs: PDFs that contain only vector graphics (e.g., an SVG exported as PDF, a CAD drawing, or a text-only document) have no images to compress. These files are already as small as they can reasonably be. Our tool will process them but may save negligible bytes or even produce a slightly larger file due to PDF structure overhead.

The diminishing-returns line: Compressing an already-compressed file a second time rarely helps. Each pass has less to work with. If the first pass reduced your 50 MB file to 18 MB, a second pass might get you to 15 MB — worthwhile maybe, but the third pass will barely budge. A practical rule: if the first pass did not achieve at least 20% reduction, a second pass will not help either.

Compression is not a universal solution. It shrinks images inside the PDF, so if your file has few or no images, compression does almost nothing.

Here is how to predict your result before you compress: Right-click the PDF and check its properties. If the file is under 5 MB and was created by a modern application (Word, Google Docs, a browser print dialog), it is probably already compressed. Expect at most 10–20% savings.

If the file is 10 MB or larger and contains scanned pages or embedded photos, you will likely see significant savings — often 40–80%. The higher the original resolution (600+ DPI scans), the bigger the reduction.

If compression delivers disappointing results on a file that should have shrunk more, the PDF may use unusual codecs or JPEG2000 compression, which our tool cannot re-encode efficiently. In that case, try converting the PDF’s images to standard JPEG before creating the PDF, then compress again.