How to Convert Between Data Storage Units
Digital data is measured in bytes and its multiples: Kilobytes (KB), Megabytes (MB), Gigabytes (GB), Terabytes (TB), and Petabytes (PB). Converting between these units is straightforward once you know the base. In the binary system used by operating systems and computer memory, each unit is 1,024 times the previous one. In the decimal (SI) system used by storage manufacturers and ISPs, each unit is 1,000 times the previous one.
This page provides 39 pre-calculated conversions covering the most commonly searched data size conversions. Each conversion page shows both the binary and decimal result so you always have the right number, whether you are checking your hard drive capacity, planning cloud storage, or estimating download sizes.
Binary vs Decimal: Why the Difference Matters
The reason your 1 TB hard drive shows as 931 GB in Windows comes down to the binary vs decimal discrepancy. Storage manufacturers define 1 TB as exactly 1,000,000,000,000 bytes (decimal), but your operating system defines 1 TB as 1,099,511,627,776 bytes (binary). Since the decimal TB is smaller, the same number of bytes translates to fewer binary TB or GB.
The International Electrotechnical Commission (IEC) introduced binary prefixes — KiB (Kibibyte), MiB (Mebibyte), GiB (Gibibyte), TiB (Tebibyte) — to eliminate this ambiguity. However, most consumers and operating systems still use the traditional KB, MB, GB, and TB abbreviations for binary values, which can cause confusion when comparing specifications.
Quick Reference: Binary Conversion Factors
| Conversion | Factor | Example |
|---|---|---|
| 1 KB | 1,024 Bytes | A short text file |
| 1 MB | 1,024 KB | A high-res photo |
| 1 GB | 1,024 MB | A short HD video |
| 1 TB | 1,024 GB | ~250 full-length movies |
| 1 PB | 1,024 TB | ~500 billion pages of text |