PDF to PDF
Reprocess and optimize PDF files for improved compression, quality settings, or format normalization. Reduce file size or enhance readability.
Convert following formats from and to PDF: DOCX, PPTX, XLSX, JPG, PNG, RTF, TXT
Frequently Asked Questions About OCR PDF to Searchable PDF
What does OCR PDF to PDF actually do?
OCR (Optical Character Recognition) converts scanned PDF pages—which are just images of text—into searchable, selectable PDFs. The output looks identical to the original but contains a hidden text layer. You can now search for words, copy paragraphs, and use screen readers. The visual appearance stays the same; only the text becomes accessible.
Why make a scanned PDF searchable instead of leaving it as-is?
Scanned PDFs are digital photos—you can't search, copy, or index the text. Searchable PDFs unlock full-text search, allow copy-paste for quotes, enable accessibility features for visually impaired users, and let search engines index the content. For archival, legal, and research documents, searchability is essential. Without OCR, your PDF is a locked image.
Which languages does OCR support?
Modern OCR engines support 100+ languages: English, Spanish, French, German, Chinese, Arabic, Russian, Japanese, and more. Multi-language documents work if you specify all present languages. Accuracy depends on font clarity and language—Latin scripts (English, French) have 98%+ accuracy; complex scripts (Arabic, Chinese) need clean scans. Always preview results for mixed-language documents.
How does scan quality affect OCR accuracy?
Clean, high-contrast scans (300 DPI, straight alignment, black text on white) yield 95-99% accuracy. Poor scans—skewed pages, faded ink, colored backgrounds, handwriting—drop accuracy to 60-80%. Pre-process scans: straighten pages, increase contrast, remove shadows. Photocopies of photocopies often fail OCR. For critical documents, rescan at 300-600 DPI if possible.
Will OCR increase my PDF file size?
Slightly. Adding a text layer increases file size by 5-20%, depending on text density. A 2MB scanned invoice might become 2.2MB. The original images remain; OCR just embeds invisible text. If file size matters, compress images first (JPEG at 150 DPI for archival, 300 DPI for print) before OCR. The searchability benefit outweighs the small size increase.
How accurate is OCR, and will it make mistakes?
OCR accuracy ranges from 85% (poor scans, handwriting) to 99.5% (clean typed text). Common errors: confusing '0' and 'O', '1' and 'l', or misreading decorative fonts. Always proofread critical documents—contracts, legal filings, academic papers. For high-stakes use, manually verify key numbers, names, and dates. OCR is excellent for bulk archival but not foolproof for precision work.