File Sizes: A Practical Guide
Know What Your Files Really Weigh
Explore File SizesWhy is that Word document 50 MB when another is only 500 KB? Why does a 5-minute video sometimes take gigabytes while other times it's just megabytes? 理解する typical file sizes helps you manage storage, estimate upload times, and choose the right format for your needs.
Document File Sizes
| File Type | Typical Size Range | What Affects Size |
|---|---|---|
| Plain text (.txt) | 1-100 KB | Character count only |
| Word (.docx) - text only | 20-100 KB | Formatting, styles |
| Word (.docx) - with images | 500 KB - 50 MB | Number and size of images |
| PDF - text only | 50-500 KB | Fonts, formatting |
| PDF - with images | 500 KB - 100+ MB | Image resolution, compression |
| Excel (.xlsx) - simple | 20-200 KB | Number of cells, formulas |
| Excel (.xlsx) - complex | 1-50 MB | Data volume, charts, macros |
| PowerPoint (.pptx) | 1-100 MB | Images, videos, slide count |
Image File Sizes
| Format | Typical Size | Best For |
|---|---|---|
| JPEG (web quality) | 100-500 KB | Web photos, social media |
| JPEG (high quality) | 1-5 MB | Prints, archives |
| PNG (simple graphics) | 50-500 KB | Logos, screenshots |
| PNG (complex/large) | 1-20 MB | Detailed graphics, transparency |
| GIF (animated) | 500 KB - 10 MB | Short animations |
| RAW (camera) | 20-80 MB | Professional photography |
| TIFF (uncompressed) | 20-200 MB | Print production |
| WebP | 50-300 KB | Modern web images |
| HEIC/HEIF | 1-3 MB | iPhone photos |
Video File Sizes
| Quality/Format | Size Per Minute | Size Per Hour |
|---|---|---|
| 480p SD (H.264) | ~10 MB | ~600 MB |
| 720p HD (H.264) | ~25 MB | ~1.5 GB |
| 1080p Full HD (H.264) | ~50 MB | ~3 GB |
| 1080p Full HD (H.265/HEVC) | ~25 MB | ~1.5 GB |
| 4K UHD (H.264) | ~200 MB | ~12 GB |
| 4K UHD (H.265/HEVC) | ~100 MB | ~6 GB |
| 4K ProRes (professional) | ~2 GB | ~120 GB |
Note: Actual sizes vary based on content complexity, bitrate settings, and codec efficiency.
Audio File Sizes
| Format | Size Per Minute | Size Per Hour | Quality |
|---|---|---|---|
| MP3 (128 kbps) | ~1 MB | ~60 MB | Acceptable |
| MP3 (320 kbps) | ~2.5 MB | ~150 MB | Good |
| AAC (256 kbps) | ~2 MB | ~120 MB | Good |
| FLAC | ~5-10 MB | ~300-600 MB | Lossless |
| WAV (CD quality) | ~10 MB | ~600 MB | Uncompressed |
| Voice recording | ~500 KB | ~30 MB | Speech only |
Software and Data Files
| File Type | Typical Size Range |
|---|---|
| Mobile app | 10 MB - 1 GB |
| PC application | 50 MB - 10 GB |
| Modern video game | 20 GB - 200 GB |
| Operating system | 5 GB - 20 GB |
| Database backup (small) | 100 MB - 10 GB |
| Website backup | 100 MB - 50 GB |
| ZIP archive | 50% - 90% of original |
Email Attachment Limits
Common maximum attachment sizes:
| Service | Attachment Limit |
|---|---|
| Gmail | 25 MB |
| Outlook.com | 20 MB |
| Yahoo Mail | 25 MB |
| iCloud Mail | 20 MB |
| Corporate email (typical) | 10-25 MB |
For larger files, use cloud storage links (Google Drive, Dropbox, OneDrive) instead of attachments.
Upload Time Estimates
Approximate upload times at different internet speeds:
| File Size | 10 Mbps | 50 Mbps | 100 Mbps |
|---|---|---|---|
| 10 MB | 8 sec | 1.6 sec | 0.8 sec |
| 100 MB | 80 sec | 16 sec | 8 sec |
| 1 GB | 14 min | 2.7 min | 1.3 min |
| 10 GB | 2.3 hr | 27 min | 13 min |
*Actual speeds may be slower due to network overhead and other factors
まとめ
理解する typical file sizes helps you plan storage needs, estimate transfer times, and troubleshoot unexpectedly large files. Documents are usually kilobytes to megabytes; photos are megabytes; videos and software can be gigabytes. When a file seems too large, check for embedded images in documents, video resolution settings, or uncompressed formats.