File Size Units Explained — KB, MB, GB and TB Conversion Guide
Updated October 2026 · 3 min read
Quick start: Open the free File Size Converter — enter any value in bytes, KB, MB, GB or TB to convert instantly.
The Units at a Glance
| Unit | Abbreviation | Decimal (SI) | Binary (IEC) |
|---|---|---|---|
| Kilobyte | KB | 1,000 bytes | 1,024 bytes (KiB) |
| Megabyte | MB | 1,000,000 bytes | 1,048,576 bytes (MiB) |
| Gigabyte | GB | 1,000,000,000 bytes | 1,073,741,824 bytes (GiB) |
| Terabyte | TB | 1,000,000,000,000 bytes | 1,099,511,627,776 bytes (TiB) |
Why Your 1TB Hard Drive Shows Less Than 1TB
Hard drive manufacturers use the decimal definition (1 TB = 1,000,000,000,000 bytes). Your operating system uses binary (1 TiB = 1,099,511,627,776 bytes). So a "1 TB" drive only reports ~931 GiB in Windows or macOS — not a defect, just a units mismatch. The larger the drive, the bigger the apparent gap.
Common File Sizes for Reference
- Plain text document (1,000 words): ~6 KB
- JPEG photo (smartphone): 2–5 MB
- MP3 audio (4 minutes): ~4–8 MB
- Full HD video (1 minute, H.264): ~150 MB
- 4K video (1 minute): ~400–800 MB
- Large software installer: 1–4 GB
Convert File Sizes Instantly
Bytes, KB, MB, GB, TB — decimal and binary. No account needed.
Open Free File Size Converter →