How to reduce pdf size by subsetting embedded fonts
- Step 1Upload the PDF with large embedded fonts — Drop the document into the font subsetter.
- Step 2Apply subsetting to all fonts — Subset each embedded font to include only the characters used in the document.
- Step 3Download the reduced PDF — Save the significantly smaller file.
- Step 4Verify text rendering — Open the PDF and confirm all characters render correctly.
Frequently asked questions
How do I know if my PDF contains large embedded fonts?+
Check File > Properties > Fonts in Acrobat. CJK fonts (e.g., 'WenQuanYi', 'MS Gothic') are often the largest. Compare with the total file size.
Will subsetting affect CJK text search in the PDF?+
No — text search uses the Unicode mapping layer in the PDF, not the font file itself. Subsetted PDFs are fully searchable.
Can I subset fonts in a PDF/A file without breaking compliance?+
Yes — font subsetting is fully compatible with PDF/A compliance. The subsetted font must include all characters present in the document.
Privacy first
All PDF processing runs locally in your browser using PDF-lib and pdf.js. No file is ever uploaded — only metadata counters are saved for signed-in dashboard stats.