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Convert

Stirling-PDF's Convert tool provides powerful file format conversion with support for 50+ file types. Convert documents, images, web pages, and more to PDF, or export PDFs to other formats.

How to Use Convert

  1. Select Source Format - Choose what you're converting from (e.g., Word, Image, PDF)
  2. Select Target Format - Choose what you're converting to (e.g., PDF, JPG, DOCX)
  3. Upload Files - Add one or multiple files depending on the conversion
  4. Configure Options - Adjust settings like image quality, color mode, layout
  5. Convert - Process and download your converted files

Supported Conversions

Convert TO PDF

Office Documents

  • Word - DOCX, DOC, ODT → PDF
  • Excel - XLSX, XLS, ODS → PDF
  • PowerPoint - PPTX, PPT, ODP → PDF
  • Text - TXT, RTF → PDF

Images

  • Formats - JPG, JPEG, PNG, GIF, BMP, TIFF, WEBP, SVG → PDF
  • Multiple Images - Combine multiple images into one PDF
  • Options:
  • Color mode (color, grayscale, black & white)
  • Fit to page or maintain aspect ratio
  • Single PDF or separate files

Web Content

  • HTML to PDF - Convert HTML files (with CSS and images via ZIP)
  • URL to PDF - Render and save web pages as PDF
  • Markdown to PDF - Convert Markdown (.md) files to formatted PDF

Email

  • EML to PDF - Convert email files (.eml format) into PDF
  • Preserves email content, formatting, and metadata

Comic Book Archives

  • CBZ to PDF - Convert Comic Book Zip files to PDF
  • CBR to PDF - Convert Comic Book RAR files to PDF

Convert FROM PDF

Office Formats

  • PDF to Word - PDF → DOCX, ODT
  • Editable documents with preserved layout
  • Best for text-heavy PDFs

  • Works better with digital PDFs than scanned ones

  • PDF to PowerPoint - PDF → PPTX, ODP

  • Each page becomes a slide

  • Useful for presentations

  • PDF to Text - PDF → TXT, RTF, MD (Markdown)

  • Extract plain text
  • Remove formatting
  • Easy to edit and search

Images

  • PDF to Image - PDF → PNG, JPG, GIF, TIFF, BMP, WEBP
  • Options:
  • Image format and quality
  • DPI (resolution)
  • Color mode (color, grayscale, black & white)
  • Single image or one per page

Data Formats

  • PDF to CSV - Extract tables from PDF to CSV
  • ⚠️ Works best with digital PDFs (not scanned)
  • Attempts to detect tables automatically

  • Work in progress feature due to complexity

  • PDF to HTML - Convert PDF to web format

  • Preserves structure and formatting

  • Can be edited with HTML editors

  • PDF to XML - Convert PDF to XML structure

  • For data processing and analysis

Archival Format

  • PDF to PDF/A - Convert to long-term archival format
  • PDF/A is ISO standardized
  • Ensures long-term readability
  • Required for compliance in many industries

Comic Book Archives

  • PDF to CBZ - Convert PDF to Comic Book Zip
  • PDF to CBR - Convert PDF to Comic Book RAR

Conversion Options

Image Quality Settings

When converting to images: - DPI (Resolution) - 72 DPI - Screen viewing, small file size - 150 DPI - Standard quality, balanced - 300 DPI - High quality, printing, large file size - Custom - Specify exact DPI

  • Color Mode
  • Color - Full color, best quality
  • Grayscale - Black and white shades, smaller file
  • Black & White - 1-bit, smallest file, sharp text

Layout Options

When converting images to PDF: - Fit to Page - Resize image to fit PDF page - Maintain Aspect Ratio - Keep original proportions - Fill Page - Stretch to fill entire page

Output Mode: - Single PDF - All files into one PDF - Separate PDFs - One PDF per input file

Batch Conversion

Convert multiple files at once:

  1. Select conversion type (e.g., Images to PDF)
  2. Upload multiple files
  3. Choose "Single PDF" or "Separate PDFs"
  4. Convert all at once
  5. Download as single file or ZIP

Supported for: - Multiple images to PDF - Multiple Office documents to PDF - PDF to multiple images (one per page)

Tips & Best Practices

For Best Results

Office to PDF: - Use original source files (DOCX, not scanned) - Check fonts are embedded - Verify hyperlinks work - Test on sample first for large documents

PDF to Office: - Works best with digital PDFs (not scanned images) - For scanned PDFs, use OCR first - Complex layouts may need manual adjustment - Check formatting after conversion

Image Conversions: - Higher DPI = better quality but larger files - Use PNG for screenshots (lossless) - Use JPG for photos (smaller) - Grayscale reduces file size significantly

Web to PDF: - URLs must be publicly accessible - For HTML files, include CSS/images in ZIP - Test with simple pages first - May timeout on very heavy pages

Common Issues

"Conversion failed" - Check file isn't corrupted - Try smaller file first - Ensure format is supported - Check file isn't password-protected

"Poor quality output" - Increase DPI for image exports - Use color mode instead of black/white - Check source file quality - Try different output format

"Tables not detected" (PDF to CSV) - Feature works best with simple tables - Only works with digital PDFs, not scanned - Consider extracting as text first - Manual cleanup may be needed

Technical Details

Processing Engine

Stirling-PDF uses industry-standard tools for conversions:

  • Office Conversions - LibreOffice (document fidelity)
  • Image Processing - ImageMagick, OpenCV
  • PDF Operations - Apache PDFBox
  • OCR - Tesseract (when needed)

Supported Formats

Input Formats (Convert TO PDF): 

Documents: DOCX, DOC, ODT, XLSX, XLS, ODS, PPTX, PPT, ODP, TXT, RTF
Images:    JPG, JPEG, PNG, GIF, BMP, TIFF, WEBP, SVG
Web:       HTML, ZIP (HTML bundle), Markdown (MD), URL
Email:     EML
Archives:  CBZ, CBR

Output Formats (Convert FROM PDF): 

Documents: DOCX, ODT, PPTX, ODP, TXT, RTF, MD
Images:    PNG, JPG, GIF, TIFF, BMP, WEBP
Data:      CSV, HTML, XML
Archive:   PDF/A, CBZ, CBR

File Size Limits

  • Web Version - Depends on browser storage (typically ~1-10GB)
  • Desktop App - No practical limit (disk space)
  • Server Deployment - Configurable in settings

For large files: - Use Desktop app for unlimited storage - Split large PDFs before converting - Process in batches - Consider compression after conversion

  • Compress - Reduce file size after conversion
  • OCR - Make scanned PDFs searchable before converting to text
  • Merge - Combine multiple converted PDFs
  • Multi-Tool - Chain conversions with other operations

API Usage

Convert files programmatically via API:

Example: Image to PDF 

curl -X POST http://stirling-pdf:8080/api/v1/convert/img/pdf \
  -F "fileInput=@image.jpg" \
  -F "colorType=color" \
  -F "fitOption=maintainAspectRatio" \
  -o output.pdf

Example: PDF to Word 

curl -X POST http://stirling-pdf:8080/api/v1/convert/pdf/word \
  -F "fileInput=@document.pdf" \
  -o output.docx

See API Documentation for complete endpoint reference.

Summary

Stirling-PDF's Convert tool provides:

✅ 50+ file format conversions ✅ Batch processing - Convert multiple files at once ✅ Quality control - Adjust DPI, color mode, layout ✅ Professional results - Industry-standard conversion engines ✅ No size limits - Desktop app handles any file size ✅ API access - Automate conversions

Perfect for document management, archiving, sharing, and workflow automation!