What does Compress PDF do?
Compress PDF is a free online tool that can reduce PDF file size using Ghostscript. The PDF result from Compress PDF is a separate copy to inspect before you use it elsewhere. One possible use is large scanned attachments prepared for email.
PDF size reduction rewrites a file with a chosen Ghostscript preset. The offered settings are screen, ebook, printer, prepress and default.
The Ghostscript presets balance the treatment of images and other file parts differently, so choose based on how the reader will read or print the output. A scan with many large images may benefit differently from a short text-only PDF.
Compare readability and file size after the task instead of expecting a fixed saving. Test a preset on the hardest page to read.
Fine chart labels can reveal blur before large headings do. A file with mostly text may have little size to save.
Keep a larger version for print if the screen copy looks soft. Check the upload portal's size rule before choosing the final version.
Reduce PDF file size online: steps
Before using Compress PDF, decide what the new copy must contain and where it will be used. Choose a preset suitable for the planned screen or print use, keeping an untouched source for comparison. Review the upload area and all values required by the current Compress PDF form.
Choose the source
Read the smallest scan text at normal zoom. For Compress PDF, choose one source from your device. Keep a source copy for another attempt.
Review the form values
Compression level controls a value used by Compress PDF. The starting Compression level value is ebook.
Run the file task
Use Process Compress PDF after checking the source and form values. Wait for the job to finish. An error means this attempt failed.
Save and check the output
Check photos, small labels, fine lines and the new file size before deciding that the preset is acceptable. Store the output on your device. Name this copy separately from the original.
Reduce size: uses for Compress PDF
Compress PDF can help with reading copies made for mobile screens. It can also be used for reports optimized before uploading to a portal. The PDF result from Compress PDF must suit the intended reading or editing step, so keep the source until that check is complete.
- Large scanned attachments prepared for email.
- Reading copies made for mobile screens.
- Reports optimized before uploading to a portal.
- Print-oriented files tested with a less aggressive preset.
Formats and limits for Compress PDF
The Compress PDF form accepts PDF sources. Each Compress PDF upload can be up to 300 MB, which equals 300 MiB. The allowed suffixes on the Compress PDF page do not prove that a source has valid content inside it.
| Accepted formats | Maximum file size | Output |
|---|---|---|
| 300 MB per file (300 MiB upload limit) |
A smaller result is not certain. Rewriting can affect fonts, clear areas, hidden file tags and signed files, especially when source content is complex.
How this tool works
Compress PDF uses Ghostscript to handle the source on the server. The Compress PDF request uses your chosen input rather than any local editing project left on your device. Check the PDF contents produced by Compress PDF before treating them as ready for another app or reader.
For Compress PDF, your browser uploads the source to our file-processing server. This is a server task, not local editing.
Files are due for deletion within 1 hour. Cleanup runs during normal service operation. Keep a local download for future use.
Compress PDF questions and answers
If Compress PDF gives an unexpected result, start by checking the source type and the values used in the form. Check the PDF contents from Compress PDF as well as the filename or displayed message. For another result type, compare Compress PDF with the separate tools described in these answers.
What matters when using Compress PDF?
Check thin plot lines before using a print-oriented result. View that area at its intended display size. Note any differences that affect your purpose.
Why try Web Optimize PDF?
Web Optimize PDF offers another task beside Compress PDF: linearize PDF for fast web viewing. Web Optimize PDF returns PDF. The stated PDF output from Compress PDF matches a listed input type for Web Optimize PDF.
Why try PDF to Grayscale?
PDF to Grayscale offers another task beside Compress PDF: convert a color PDF to grayscale. PDF to Grayscale returns PDF. The stated PDF output from Compress PDF matches a listed input type for PDF to Grayscale.
Why try Repair PDF?
Repair PDF offers another task beside Compress PDF: attempt to rebuild a broken PDF structure. Repair PDF returns PDF. The stated PDF output from Compress PDF matches a listed input type for Repair PDF.
What if my PDF result does not open?
For a failed Compress PDF result, first confirm that the download completed and that the viewer supports PDF. Try another local viewer for that format.
Record any error message for support. Keep private source material out of the report.
How do I report a problem with Compress PDF?
Contact support with the Compress PDF page name, source format and the error you saw. Mention any relevant form settings you chose. Do not send passwords or private attachments.