Decimal units
Storage manufacturers and many software interfaces use decimal prefixes: 1 GB = 1,000 MB.
Binary units
Binary units use powers of 1024: 1 GiB = 1,024 MiB. The labels KiB, MiB, GiB and TiB identify this system.
Why the distinction matters
A converter should not silently treat MB and MiB as the same unit. Tervilo keeps the two systems separate.
Decimal Storage Units
Decimal storage units use powers of 1000. Therefore, 1 GB = 1,000 MB and 1 TB = 1,000 GB.
Binary Storage Units
Binary units use powers of 1024. Therefore, 1 GiB = 1,024 MiB and 1 TiB = 1,024 GiB.
Why GB and GiB Are Different
GB and GiB are not interchangeable labels. A value expressed in GB uses the decimal convention, while a value expressed in GiB uses the binary convention. Storage manufacturers, operating systems and technical specifications may use different conventions.
Worked Examples
- 1 GB = 1,000 MB.
- 1 GiB = 1,024 MiB.
- 2 GB = 2,000 MB.
- 2 GiB = 2,048 MiB.
How to Avoid Confusion
Read the unit label before comparing two file sizes or storage capacities. Do not convert MB to MiB by simply treating both as the same unit. The decimal and binary systems must remain distinct.
Use the Tervilo Data Storage Converter
Use the Tervilo Data Storage Converter when you need to compare decimal and binary storage units.
Why MB and MiB Are Different
MB and MiB are not two spellings for the same unit. MB means megabyte and uses the decimal SI prefix, while MiB means mebibyte and uses the binary IEC prefix.
Similarly, GB means gigabyte and GiB means gibibyte. The distinction matters when comparing storage specifications with operating-system displays or technical documentation.
Decimal Storage Units
Decimal prefixes use powers of 1,000:
- 1 KB = 1,000 bytes
- 1 MB = 1,000,000 bytes
- 1 GB = 1,000,000,000 bytes
Binary Storage Units
Binary prefixes use powers of 1,024:
- 1 KiB = 1,024 bytes
- 1 MiB = 1,048,576 bytes
- 1 GiB = 1,073,741,824 bytes
MB to MiB and GB to GiB
Because the units use different definitions, the numerical values are not identical.
For example, 1 GB is approximately 0.9313 GiB. Likewise, 1 MB is approximately 0.9537 MiB.
Why Storage Sizes Can Look Different
A storage device may be advertised using decimal GB or TB units, while software may report capacity using binary calculations or may use the GB label for a binary value. This can make the displayed number appear smaller than the advertised capacity even when the underlying storage has not changed.
Worked Examples
| Decimal Value | Approximate Binary Value |
|---|---|
| 1 MB | 0.9537 MiB |
| 100 MB | 95.37 MiB |
| 1 GB | 0.9313 GiB |
| 10 GB | 9.3132 GiB |
Common MB, GB, MiB and GiB Mistakes
- Treating MB and MiB as identical units.
- Treating GB and GiB as identical units.
- Assuming every operating system uses the same naming convention.
- Using 1,024 as the conversion factor between decimal and binary prefixes without accounting for the different base definitions.
Use the Tervilo Storage Unit Converter
Choose the exact source and target units when converting storage values. When comparing a manufacturer specification with a software display, first determine whether each value is expressed using decimal or binary prefixes.