変換方法 GB to MB
Mastering Digital Storage Conversions
Get the FormulaConverting between gigabytes and megabytes should be simple—but there's a catch. The computer industry uses two different standards: the decimal system (1 GB = 1,000 MB) and the binary system (1 GiB = 1,024 MiB). 理解する both systems helps you interpret storage specifications accurately.
The Conversion Formula
Decimal (Most Common)
Megabytes = Gigabytes × 1,000
Gigabytes = Megabytes ÷ 1,000
Examples
- 2 GB = 2 × 1,000 = 2,000 MB
- 4.5 GB = 4.5 × 1,000 = 4,500 MB
- 500 MB = 500 ÷ 1,000 = 0.5 GB
- 1,500 MB = 1,500 ÷ 1,000 = 1.5 GB
Conversion Table
| Gigabytes (GB) | Megabytes (MB) | 一般的な用途 |
|---|---|---|
| 0.1 GB | 100 MB | Small app |
| 0.5 GB | 500 MB | Large app |
| 1 GB | 1,000 MB | HD movie |
| 4 GB | 4,000 MB | DVD capacity |
| 8 GB | 8,000 MB | Dual-layer DVD |
| 16 GB | 16,000 MB | Small memory card |
| 32 GB | 32,000 MB | Basic phone storage |
| 64 GB | 64,000 MB | Standard phone storage |
| 128 GB | 128,000 MB | Large phone storage |
| 256 GB | 256,000 MB | Laptop SSD |
| 1,000 GB | 1,000,000 MB | 1 TB |
Why Two Standards Exist
The Decimal Standard (SI)
Based on powers of 10, matching the メートル法:
- 1 Kilobyte (KB) = 1,000 bytes
- 1 Megabyte (MB) = 1,000 KB = 1,000,000 bytes
- 1 Gigabyte (GB) = 1,000 MB = 1,000,000,000 bytes
Used by: Hard drive manufacturers, phone storage, most consumer contexts.
The Binary Standard (IEC)
Based on powers of 2, matching how computers actually address memory:
- 1 Kibibyte (KiB) = 1,024 bytes
- 1 Mebibyte (MiB) = 1,024 KiB = 1,048,576 bytes
- 1 Gibibyte (GiB) = 1,024 MiB = 1,073,741,824 bytes
Used by: RAM specifications, Windows file sizes, some software.
Binary Conversion Table
For technical contexts using binary units:
| Gibibytes (GiB) | Mebibytes (MiB) | Formula |
|---|---|---|
| 1 GiB | 1,024 MiB | × 1,024 |
| 2 GiB | 2,048 MiB | 2 × 1,024 |
| 4 GiB | 4,096 MiB | 4 × 1,024 |
| 8 GiB | 8,192 MiB | 8 × 1,024 |
| 16 GiB | 16,384 MiB | 16 × 1,024 |
Complete Storage Hierarchy
Decimal (SI) Units
| Unit | Bytes | Equivalent |
|---|---|---|
| Kilobyte (KB) | 1,000 | 1,000 bytes |
| Megabyte (MB) | 1,000,000 | 1,000 KB |
| Gigabyte (GB) | 1,000,000,000 | 1,000 MB |
| Terabyte (TB) | 1,000,000,000,000 | 1,000 GB |
Binary (IEC) Units
| Unit | Bytes | Equivalent |
|---|---|---|
| Kibibyte (KiB) | 1,024 | 1,024 bytes |
| Mebibyte (MiB) | 1,048,576 | 1,024 KiB |
| Gibibyte (GiB) | 1,073,741,824 | 1,024 MiB |
| Tebibyte (TiB) | 1,099,511,627,776 | 1,024 GiB |
まとめ
Converting GB to MB is straightforward: multiply by 1,000 (decimal) or 1,024 (binary). Most everyday situations use the decimal standard where 1 GB = 1,000 MB. The binary standard (1 GiB = 1,024 MiB) appears in technical contexts like RAM specifications and Windows file properties.
When in doubt, use the decimal conversion (×1,000)—it's what manufacturers and most consumer products use.