# 数据存储单位换算器

> 将 GB 换算为 MB、TB 换算为 GB、GiB 换算为 GB，明确区分十进制前缀（kB、MB、GB、TB）和二进制前缀（KiB、MiB、GiB、TiB），并支持比特和字节。

交互版本：https://www.calcopenly.com/zh/conversion/data-storage-converter
主题：单位换算器

Data sizes use two sets of prefixes. The decimal ones follow the SI: 1 kB = 1,000 bytes, 1 MB = 10⁶ and 1 GB = 10⁹ bytes. The binary ones, approved by the IEC in December 1998 and now part of IEC 80000-13, step by 1,024: 1 KiB = 1,024 bytes, 1 MiB = 2²⁰ and 1 GiB = 2³⁰ bytes. A byte is 8 bits, and every conversion between these units is exact.

The default converts 1 GiB to 1,073.741824 MB. The same gap explains why a new drive looks smaller: a 1 TB drive holds 10¹² bytes, which software counting in binary units shows as 931.32 GiB, often labelled “931 GB”.

The gap grows with each prefix: 2.4% at kilo, 7.37% at giga, 9.95% at tera and 20.9% at yotta. Memory chips come in powers of two, so RAM sizes are binary even when written GB, while drive makers and network speeds use decimal prefixes.

## 输入

- **数值**: 输入源单位下的数值，也可以输入带有自身单位的数值
- **从** (选项：bit, nibble, byte (B), kilobyte (kB), megabyte (MB), gigabyte (GB), terabyte (TB), petabyte (PB), exabyte (EB), zettabyte (ZB), yottabyte (YB), kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB), pebibyte (PiB), exbibyte (EiB), zebibyte (ZiB), yobibyte (YiB), kilobit (kbit), megabit (Mbit), gigabit (Gbit), terabit (Tbit), kibibit (Kibit), mebibit (Mibit))
- **到** (选项：bit, nibble, byte (B), kilobyte (kB), megabyte (MB), gigabyte (GB), terabyte (TB), petabyte (PB), exabyte (EB), zettabyte (ZB), yottabyte (YB), kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB), pebibyte (PiB), exbibyte (EiB), zebibyte (ZiB), yobibyte (YiB), kilobit (kbit), megabit (Mbit), gigabit (Gbit), terabit (Tbit), kibibit (Kibit), mebibit (Mibit))

## 结果

- 转换后的数值 — 主要结果
- 换算
- 换算系数
- 精确性

## 公式

$$
\begin{gathered} x_{\text{to}} = x_{\text{from}} \times \dfrac{f_{\text{from}}}{f_{\text{to}}} \\ f = \text{one unit expressed in } \text{bit} \end{gathered}
$$

## 计算示例

### 1 GiB in MB

- 数值: 1 GiB
- 从: gibibyte (GiB)
- 到: megabyte (MB)
- **转换后的数值: 1,073.741824 MB**
- **精确性: 精确**
- 核验来源：2³⁰ bytes = 1,073,741,824 bytes (IEC 80000-13); ÷ 10⁶

### A 1 TB drive in GiB

- 数值: 1 TB
- 从: terabyte (TB)
- 到: gibibyte (GiB)
- **转换后的数值: 931.322574615 GiB**
- 核验来源：10¹² / 2³⁰ = 244140625/262144, a terminating decimal (Python fractions)

### 1 KiB in kB

- 数值: 1 KiB
- 从: kibibyte (KiB)
- 到: kilobyte (kB)
- **转换后的数值: 1.024 kB**
- 核验来源：1024 bytes / 1000 bytes

### Largest gap: 1 YiB in YB

- 数值: 1 YiB
- 从: yobibyte (YiB)
- 到: yottabyte (YB)
- **转换后的数值: 1.20892581961 YB**
- 核验来源：2⁸⁰ / 10²⁴ = 1.208925819614629174706176 exactly (Python fractions)

### 1 byte in bits

- 数值: 1 B
- 从: byte (B)
- 到: bit
- **转换后的数值: 8 bit**
- 核验来源：1 byte = 8 bits (IEC 80000-13)

## 常见问题

### Why does my 1 TB drive show only 931 GB?

Because the maker and the operating system count differently. The drive's 1 TB is 10¹² bytes; Windows divides by 2³⁰ and shows 931.32 while labelling it GB. Nothing is missing, since 10¹² ÷ 1,073,741,824 = 931.32; formatting and recovery partitions take a little more. macOS has counted in decimal since OS X 10.6 and shows the same drive as 1 TB.

### Is 1 GB 1,000 MB or 1,024 MB?

Under the SI and IEC 80000-13, 1 GB is exactly 1,000 MB (10⁹ bytes), and the binary unit is 1 GiB = 1,024 MiB (2³⁰ bytes). Drive makers and macOS use the decimal meaning; RAM and Windows use the binary one while writing GB. The “1.44 MB” floppy disk mixed the two: 1,440 × 1,024 bytes.

### How many bits are in a byte?

Eight. IEC 80000-13 defines the byte as 8 bits, also called an octet. File sizes are counted in bytes (B) and network speeds in bits per second (bit/s), so a 100 Mbit/s connection moves at most 12.5 MB per second; a capital B marks bytes.

### What is a GiB?

A gibibyte, 2³⁰ = 1,073,741,824 bytes. The IEC created the binary prefixes kibi, mebi, gibi and tebi so that kilo, mega and giga could keep their SI meanings of 10³, 10⁶ and 10⁹. Many Linux tools and technical specifications use GiB; Windows shows the same quantity labelled GB.

### How many GB are in 1 TB?

1,000 GB in decimal units, which is how drives are sold. In binary units 1 TiB is 1,024 GiB, and a decimal 1 TB is 931.32 GiB. The converter keeps TB, TiB, GB and GiB separate, so you can see that 1 TiB is 1,099.51 GB, about 10% more than 1 TB.

### “数据存储单位换算器”有多准确？

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字，但估算、数值方法和源数据的精度可能较低；显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例：5。 例如，“1 GiB in MB”根据2³⁰ bytes = 1,073,741,824 bytes (IEC 80000-13); ÷ 10⁶进行核验。

### 这种方法出自哪里？

NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors; NIST Handbook 44, Appendix C — General tables of units of measurement; NIST — Prefixes for binary multiples (IEC 80000-13).

## 来源

- [NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C — General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)
- [NIST — Prefixes for binary multiples (IEC 80000-13)](https://physics.nist.gov/cuu/Units/binary.html)