FAQ
Frequently Asked Questions
Everything you need to know about PDFSize.
How does PDFSize compress PDFs?
We use our proprietary SuperCompressor engine that reduces image quality, removes redundant data, and optimises the internal structure of your PDF.
Why couldn't you reach my target size?
PDF compression has natural limits. Text-only PDFs are already very efficient. Try Extreme mode or Custom for maximum compression.
Is my PDF safe?
Yes. Your file is encrypted in transit, processed automatically, and permanently deleted immediately after you download your result.
What is the maximum file size?
We support PDF files up to 50MB.
Can I compress multiple PDFs at once?
Batch compression is coming soon! Currently one file at a time.
What do the 4 compression modes do?
Basic preserves maximum quality. Balanced is a good middle ground. Extreme gives the smallest file. Custom lets you specify an exact KB target.