Why does my hard drive have less space than advertised?

Hard drives use decimal units (1 KB = 1,000 bytes) for marketing, but computers use binary units (1 KB = 1,024 bytes). A "1 TB" drive contains 1 trillion bytes, which equals about 931 GiB (gibibytes) in binary. The difference accumulates with larger drives.

What is the difference between MB, MiB, GB, and GiB?

MB (megabyte) = 1,000,000 bytes (decimal). MiB (mebibyte) = 1,048,576 bytes (binary). Similarly, GB = 1 billion bytes (decimal), while GiB = 1,073,741,824 bytes (binary). Use MiB/GiB/TiB for accurate computer measurements.

How much data can I store on a 256 GB SSD?

A 256 GB SSD can store approximately 256 billion bytes in decimal terms, or about 238 GiB in binary terms. Accounting for system files and formatting, usable space is typically around 230 GiB.

Data Storage Converter

Convert data storage units including bytes, KB, MB, GB, TB, and more.

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MB to MiB MiB to MB GB to GiB TB to TiB KB to KiB

Complete List of Data Storage Units for Conversion

1 Bit [bit] = 0.125000 Byte [B]

Bit to Byte, Byte to Bit

1 Kilobyte (Decimal) [KB] = 1000.00 Byte [B]

Kilobyte (Decimal) to Byte, Byte to Kilobyte (Decimal)

1 Kibibyte [KiB] = 1024.00 Byte [B]

Kibibyte to Byte, Byte to Kibibyte

1 Megabyte (Decimal) [MB] = 1.00000e+6 Byte [B]

Megabyte (Decimal) to Byte, Byte to Megabyte (Decimal)

1 Mebibyte [MiB] = 1.04858e+6 Byte [B]

Mebibyte to Byte, Byte to Mebibyte

1 Gigabyte (Decimal) [GB] = 1.00000e+9 Byte [B]

Gigabyte (Decimal) to Byte, Byte to Gigabyte (Decimal)

1 Gibibyte [GiB] = 1.07374e+9 Byte [B]

Gibibyte to Byte, Byte to Gibibyte

1 Terabyte (Decimal) [TB] = 1.00000e+12 Byte [B]

Terabyte (Decimal) to Byte, Byte to Terabyte (Decimal)

1 Tebibyte [TiB] = 1.09951e+12 Byte [B]

Tebibyte to Byte, Byte to Tebibyte

1 Petabyte (Decimal) [PB] = 1.00000e+15 Byte [B]

Petabyte (Decimal) to Byte, Byte to Petabyte (Decimal)

1 Pebibyte [PiB] = 1.12590e+15 Byte [B]

Pebibyte to Byte, Byte to Pebibyte

Understanding data storage units

The byte is the fundamental unit of digital data storage. One byte represents 8 bits and can store one character of text. Larger units like kilobytes (KB), megabytes (MB), gigabytes (GB), and terabytes (TB) represent increasing multiples of bytes.

Binary vs Decimal data storage units

1 kilobyte (KB) = 1,000 bytes (decimal) or 1,024 bytes (binary)
1 megabyte (MB) = 1,000,000 bytes (decimal) or 1,048,576 bytes (binary)
1 gigabyte (GB) = 1,000,000,000 bytes (decimal) or 1,073,741,824 bytes (binary)
1 terabyte (TB) = 1,000,000,000,000 bytes (decimal) or 1,099,511,627,776 bytes (binary)
1 mebibyte (MiB) = 1,048,576 bytes (binary, more precise than MB)

Why binary and decimal differ

Computer systems use binary (powers of 2), so 1 kilobyte technically equals 1,024 bytes. However, storage manufacturers often use decimal (powers of 10) for marketing purposes, so they label 1,000 bytes as 1 KB. This difference becomes significant with larger storage amounts. For example, a "1 TB" hard drive is actually about 931 GB in binary terms.

Data storage applications

Understanding data storage units is essential for purchasing storage devices, downloading files, and managing cloud storage. File sizes (documents, images, videos) are measured in these units. RAM, hard drives, SSDs, and cloud storage all use these measurements.

Frequently Asked Questions

Why does my hard drive have less space than advertised?: Hard drives use decimal units (1 KB = 1,000 bytes) for marketing, but computers use binary units (1 KB = 1,024 bytes). A "1 TB" drive contains 1 trillion bytes, which equals about 931 GiB (gibibytes) in binary. The difference accumulates with larger drives.
What is the difference between MB, MiB, GB, and GiB?: MB (megabyte) = 1,000,000 bytes (decimal). MiB (mebibyte) = 1,048,576 bytes (binary). Similarly, GB = 1 billion bytes (decimal), while GiB = 1,073,741,824 bytes (binary). Use MiB/GiB/TiB for accurate computer measurements.
How much data can I store on a 256 GB SSD?: A 256 GB SSD can store approximately 256 billion bytes in decimal terms, or about 238 GiB in binary terms. Accounting for system files and formatting, usable space is typically around 230 GiB.

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