Start with medium compression
Medium compression is the best first attempt for most everyday PDF files because it balances size reduction and readability.
- Use less compression when the PDF contains important images, signatures, or scanned pages.
- Use extreme compression only when the upload limit matters more than image sharpness.
- Keep the original PDF until the compressed copy has been reviewed.
Check why the file is large
PDFs usually become large because of scanned pages, high-resolution photos, embedded fonts, or repeated images. A browser compressor can help, but already-optimized PDFs may not shrink much.
Review the result before upload
Open the compressed PDF and check page order, text clarity, image quality, signatures, forms, and important details before submitting it to a portal or sending it to someone else.
Related free tools
Related Mirown guides
Frequently asked questions
Why is my PDF still over 5MB after compression?
The PDF may already be optimized or may contain scanned images that cannot shrink much without visible quality loss. Try resizing source images or removing unnecessary pages if possible.
Can I compress a confidential PDF in the browser?
Mirown PDF compression is designed as a browser-first workflow for supported files, but you should still decide whether any website is appropriate for your document and keep originals safe.