PDF File Size
The byte count of a PDF file — driven mostly by embedded images and fonts. Reducing file size usually means compressing images, not text.
PDF file size varies wildly based on content. A text-only 10-page report might be 100 KB; a 10-page design portfolio with embedded high-resolution photos could be 50 MB. Understanding what drives file size helps you decide whether — and how — to compress.
What takes up space in a PDF
Ranked roughly by contribution to typical file sizes:
1. Embedded images — photos, scans, diagrams. Usually 80%+ of the file size in image-heavy documents
2. Embedded fonts — 100 KB to 1 MB per font. Subset embedding (only the used characters) cuts this dramatically
3. Vector graphics — logos, charts, line art. Surprisingly compact
4. Text content — the actual characters. Almost negligible for most documents
5. Metadata, form fields, annotations — tiny in most cases
What compression can and can't do
- Can help a lot: documents with many large photos, scanned pages, or unused-character-heavy fonts
- Won't help much: text-dominant documents that are already small, or files where every image is already near its quality floor
- Won't help at all: already-compressed documents (running the same tool twice rarely saves more)
Typical size expectations
- Text-only 1-page letter — 30-100 KB
- 10-page report with logos — 200 KB - 2 MB
- Scanned 10-page document at 300 DPI — 5-15 MB
- Image-heavy 20-page portfolio — 20-80 MB
- Book-length PDF (300 pages) — varies wildly, 1 MB (text) to 500 MB (scanned)
Email attachment limits
Common limits to plan around:
- Gmail, Outlook — 25 MB
- Apple Mail — 20 MB (upgraded to Mail Drop for larger)
- Corporate email — often 10 MB or less
- Government submission portals — often 5 MB or less
Use Compress PDF to get under the relevant cap.