File Format Reference

Comprehensive technical guides for popular file formats. Understand the strengths, limitations, and best uses for each format.

Documents

PDF

Portable Document Format

CompressionLossless

Best for: Preserving document layout, Printing

DOCX

Microsoft Word Open XML Document

CompressionLossless

Best for: Editable documents, Word processing

XLSX

Microsoft Excel Open XML Spreadsheet

CompressionLossless

Best for: Spreadsheets with formulas, Data analysis

Images

JPG

Joint Photographic Experts Group

CompressionLossy

Best for: Photographs, Web images

PNG

Portable Network Graphics

CompressionLossless

TransparencyYes

Best for: Graphics with transparency, Screenshots

HEIC

High Efficiency Image Container

CompressionLossy

TransparencyYes

Best for: iPhone and iPad photos, High-quality photos with small file size

Format Comparison Matrix

Format	Type	Compression	Transparency	Editable	Best For
PDF	document	Lossless	✕	✕	Preserving document layout
DOCX	document	Lossless	✕	✓	Editable documents
XLSX	document	Lossless	✕	✓	Spreadsheets with formulas
JPG	image	Lossy	✕	✓	Photographs
PNG	image	Lossless	✓	✓	Graphics with transparency
HEIC	image	Lossy	✓	✓	iPhone and iPad photos