GB to KB converter

Understanding data storage units

Data storage units quantify digital information. The smallest unit is the bit (binary digit), and eight bits form a byte. Larger units include:

• Kilobyte (KB) or kibibyte (KiB)
• Megabyte (MB) or mebibyte (MiB)
• Gigabyte (GB) or gibibyte (GiB)

Two systems govern these units:

1. Base-10 (SI system): Follows the International System of Units, using powers of 10.
2. Base-2 (IEC standard): Follows the International Electrotechnical Commission standard, using powers of 2.

Base-10 (SI) vs. Base-2 (IEC) systems

Base-10 (SI)

Used by storage manufacturers (e.g., hard drives, USB drives). Units include:

• 1 kilobyte (KB) = $10^3$ bytes = 1,000 bytes
• 1 megabyte (MB) = $10^6$ bytes
• 1 gigabyte (GB) = $10^9$ bytes

Base-2 (IEC)

Used by operating systems like Windows and some Linux tools. Units include:

• 1 kibibyte (KiB) = $2^{10}$ bytes = 1,024 bytes
• 1 mebibyte (MiB) = $2^{20}$ bytes
• 1 gibibyte (GiB) = $2^{30}$ bytes

Note: macOS uses SI units (e.g., 1 GB = 1,000,000,000 bytes) for storage reporting.

Example: A 256 GB SSD marketed by a manufacturer contains $256 \times 10^9$ bytes. However, Windows will display it as approximately 238.4 GiB ($256,000,000,000 \div 1,073,741,824$).

Formula

Converting GB to KB (SI)

Converting GiB to KiB (IEC)

Reverse conversions

• KB to GB: $\text{GB} = \text{KB} \div 10^6$
• KiB to GiB: $\text{GiB} = \text{KiB} \div 1,048,576$

Examples

Example 1: SI system

Convert 5 GB to KB:

Example 2: IEC system

Convert 3 GiB to KiB:

Example 3: Mixed units

A video file is 2.5 GB. How many KB is this?

Notes

1. Context matters: Operating systems often report storage in GiB but label it as “GB,” causing confusion.
2. Precision: Use 1,048,576 for IEC conversions instead of approximating to 1,000,000.
3. Online tools: Verify results using reliable converters that distinguish between SI and IEC units.

Historical context

Before 1998, “kilobyte” ambiguously referred to both 1,000 and 1,024 bytes. The IEC introduced kibibytes (KiB), mebibytes (MiB), and gibibytes (GiB) to resolve this. Despite this, many software tools still use “KB” or “GB” for base-2 units.

Frequently asked questions

How many KB are in a GB?

In the SI system:

In the IEC system (though technically GB is not part of IEC):

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

Storage manufacturers use SI units, while operating systems use IEC:

How to convert 4.7 GB to KiB?

First, convert GB to bytes (SI), then to KiB (IEC):

Are file sizes measured in SI or IEC units?

File sizes in operating systems (e.g., Windows) use IEC units but are often mislabeled as SI. A “1 MB file” is actually 1,048,576 bytes (1 MiB).

Is 1 KB equal to 1,000 or 1,024 bytes?

Depends on the context:

• SI: 1 KB = 1,000 bytes.
• IEC: 1 KiB = 1,024 bytes. Most systems use 1,024 bytes for “KB” informally, leading to inconsistency.

Summary of key points

• SI (Base-10): Used by storage manufacturers (e.g., 1 GB = 1,000,000,000 bytes).
• IEC (Base-2): Used by Windows and some software (e.g., 1 GiB = 1,073,741,824 bytes), often mislabeled as ‘GB.’