MD vs PDF
Markdown と PDF Document を徹底比較 — ファイルサイズ、品質、互換性、そして用途に応じた最適なフォーマットの選び方を解説します。
Markdown
Documents & TextMarkdown is a lightweight markup language that uses plain text formatting syntax. It is widely used in software development, technical documentation, and content management systems.
MD ファイルについてPDF Document
Documents & TextPDF is the universal standard for sharing documents with consistent formatting across all devices and operating systems. It preserves fonts, images, and layout exactly as intended by the author.
PDF ファイルについて長所の比較
MD 長所
- Readable as plain text even before rendering — fits in version control beautifully.
- Dead-simple: 90% of needs covered in 10 minutes of learning.
- Converts trivially to HTML, PDF, EPUB, and DOCX via Pandoc.
- Every modern IDE, note-taking app, and developer tool renders it natively.
- Lightweight — a typical Markdown file is kilobytes, not megabytes.
PDF 長所
- Pixel-perfect fidelity across operating systems, browsers, and printers.
- Embeds fonts, so documents render identically without the reader having them installed.
- Supports digital signatures, encryption, and redaction for legal workflows.
- ISO-standardized (ISO 32000) with multiple validated subsets (PDF/A, PDF/X, PDF/UA).
- Supports both vector and raster content, keeping line art crisp at any zoom level.
制限・弱点
MD 制限・弱点
- No formal authoritative spec — CommonMark, GFM, and MultiMarkdown differ on edge cases.
- Tables and complex layouts are clunky; footnotes and math require extensions.
- Links to images stay external — no embedded media unless you base64-inline.
- Styling is limited to what HTML allows — custom branding requires CSS outside Markdown.
PDF 制限・弱点
- Editing is difficult — the format is optimized for display, not mutation.
- Text extraction can scramble reading order in multi-column layouts.
- File sizes balloon quickly when embedding high-resolution images or fonts.
- Accessibility (screen readers) requires careful tagging that many PDFs skip.
- JavaScript support has historically been a malware vector.
技術仕様
| 仕様項目 | MD | |
|---|---|---|
| MIME type | text/markdown | application/pdf |
| Extensions | .md, .markdown, .mdown, .mkd | — |
| Standard | CommonMark, GitHub Flavored Markdown (GFM) | — |
| Encoding | UTF-8 (conventional) | — |
| Companion spec | RFC 7763 (2016) | — |
| Current version | — | PDF 2.0 (ISO 32000-2:2020) |
| Compression | — | Flate, LZW, JBIG2, JPEG, JPEG 2000 |
| Max file size | — | ~10 GB (practical); 2^31 bytes (theoretical per object) |
| Color models | — | RGB, CMYK, Grayscale, Lab, DeviceN, ICC-based |
| Standard subsets | — | PDF/A, PDF/X, PDF/UA, PDF/E, PDF/VT |
一般的なファイルサイズ
MD
- README 1-15 KB
- Blog post 2-30 KB
- Full technical manual 50 KB - 2 MB
- 1-page text-only memo 50–150 KB
- 10-page report with images 500 KB – 2 MB
- Scanned document (per page) 100 KB – 1 MB
- Full-color magazine (48 pages) 10–40 MB
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よくある 質問
Markdown is a lightweight text-based markup language created by John Gruber and Aaron Swartz in 2004. A .md file uses simple conventions (*italic*, **bold**, # headings, - lists) that compile to HTML. It became the default writing format for GitHub READMEs, Stack Overflow posts, Discord messages, and most developer documentation.
Markdown files are plain text — open in any text editor. For formatted preview use VS Code (built-in preview), Typora, Obsidian, or upload to GitHub/GitLab which render Markdown automatically. Every note-taking app (Notion, Bear, Joplin) handles Markdown natively.
Use KaijuConverter's Markdown-to-PDF converter, or command-line Pandoc (the gold standard — installed with one command, converts MD to PDF/HTML/DOCX/EPUB in a single line). VS Code with Markdown PDF extension also works locally.
Markdown for almost everything — it's 10× faster to write, version-control-friendly, and compiles to HTML automatically. Write raw HTML only when you need fine control over layout, embedded JavaScript, or features Markdown doesn't support (complex tables, forms). Static-site generators (Hugo, Astro, Jekyll) compile MD to HTML for you.
Markdown never had a formal spec for its first decade. CommonMark (2014) and GitHub Flavored Markdown (2017) standardized the core syntax, but edge cases (nested lists, HTML embedding, table syntax) still differ across renderers. For portability, stick to basic GFM features.
Yes — most modern doc tools are built on Markdown. MkDocs, Docusaurus, Astro Starlight, GitBook, and Read the Docs all accept Markdown input. For documentation needing rich features (tabs, callouts, versioning), MDX (Markdown + JSX components) extends MD with React-style embeds.