About the Data Storage Converter

The data storage converter translates between bits, bytes, and the metric (decimal) and binary prefixes used for digital storage. It handles both the kilobyte-megabyte-gigabyte family (which uses powers of 1000) and the kibibyte-mebibyte-gibibyte family (which uses powers of 1024), making it easy to convert between the two conventions that have caused confusion since the early days of computing.

The confusion arises because storage manufacturers use decimal prefixes (1 KB = 1000 bytes) while operating systems historically used binary prefixes (1 KB = 1024 bytes) without distinguishing them. This is why a 500 GB hard drive shows up as about 465 GB in some operating systems: the drive has 500 billion bytes, but the operating system divides by 1024 three times, getting 465 "binary" gigabytes. The binary prefixes (kibi, mebi, gibi) were introduced in 1998 to resolve this ambiguity.

This converter uses the byte as its base unit and applies the correct factor for each prefix. One byte equals eight bits, and all larger units are multiples of the byte. The converter handles the full range from single bits to petabytes and tebibytes.

How It Works

Each unit has a defined relationship to the byte. The converter distinguishes between decimal (SI) prefixes, which use powers of 1000, and binary (IEC) prefixes, which use powers of 1024:

Decimal (SI) prefixes:
1 B    = 1 byte
1 KB   = 1,000 B           (10^3)
1 MB   = 1,000,000 B       (10^6)
1 GB   = 1,000,000,000 B   (10^9)
1 TB   = 10^12 B
1 PB   = 10^15 B

Binary (IEC) prefixes:
1 KiB  = 1,024 B           (2^10)
1 MiB  = 1,048,576 B       (2^20)
1 GiB  = 1,073,741,824 B   (2^30)
1 TiB  = 2^40 B

1 byte = 8 bits

Every conversion proceeds in two steps: the input is multiplied by the source unit's factor to give a number of bytes, then divided by the target unit's factor to give the result in the target unit. The factor for each unit is exact, so the only source of error is floating-point rounding for very large or very small results.

The difference between the two conventions grows with the size of the prefix. One kilobyte is 2.4% smaller than one kibibyte, one megabyte is 4.9% smaller than one mebibyte, and one gigabyte is 7.4% smaller than one gibibyte. By the time you reach terabytes, the difference is nearly 10%, which is why a 1 TB drive appears to hold only about 931 GiB.

Worked Examples

To convert 1 gibibyte to gigabytes, the calculation is 1073741824 / 1000000000 = 1.0737 GB. This shows that one gibibyte is about 7.4% larger than one gigabyte, which explains the apparent capacity loss when a drive labelled in decimal gigabytes is read by an operating system using binary gigabytes.

To convert 500 gigabytes to gibibytes, the calculation is 500 * 1000000000 / 1073741824 = 465.66 GiB. This is why a 500 GB hard drive shows up as approximately 465 GB in Windows, which uses binary gigabytes (mislabelled as GB) rather than decimal gigabytes.

To convert 8 bits to bytes, the calculation is 8 * 0.125 = 1 byte. This is the fundamental relationship between bits and bytes, and it is why internet speeds (quoted in bits per second) appear eight times slower when expressed in bytes per second (the unit most file sizes use).

When to Use This Tool

Use the data storage converter whenever you need to translate between data units:

Comparing hard drive capacities labelled in decimal gigabytes with operating system readings in binary gigabytes.
Converting between network speeds (bits per second) and file sizes (bytes).
Calculating cloud storage costs quoted per gigabyte or per terabyte.
Estimating backup capacity requirements for a database or file server.
Interpreting RAM sizes, which use binary prefixes (kibibytes, mebibytes).
Converting between data transfer quotas in different units.
Teaching the difference between decimal and binary data prefixes.

Limitations & Disclaimer

This converter handles common storage units from bits to petabytes and tebibytes. It does not convert network bandwidth units (bits per second, with their own prefix conventions), data rate units, or specialised units like nibbles, words, or machine-specific page sizes. For very large or very small values, results may be displayed in scientific notation. See our disclaimer for full details.

Frequently Asked Questions

What is the difference between a kilobyte and a kibibyte?

A kilobyte (KB) is 1000 bytes, using the decimal SI prefix. A kibibyte (KiB) is 1024 bytes, using the binary IEC prefix. The two differ by about 2.4%. The binary prefixes were introduced in 1998 to resolve the ambiguity caused by operating systems using KB to mean 1024 bytes, which conflicted with the SI standard.

Why does my 500 GB hard drive show up as 465 GB?

Because the drive manufacturer uses decimal gigabytes (1 GB = 1 billion bytes), so 500 GB is 500 billion bytes. The operating system uses binary gigabytes (1 GB = 1.073 billion bytes), so it divides 500 billion by 1.074 billion and gets 465. The drive has exactly the capacity advertised; the discrepancy is a unit mismatch.

What is the difference between a bit and a byte?

A bit is a single binary digit (0 or 1), the smallest unit of digital information. A byte is 8 bits, the smallest addressable unit of memory in most computer architectures. Network speeds are quoted in bits per second, while file sizes are quoted in bytes, which is why a 100 Mbps connection downloads at about 12.5 MB per second.

Should I use decimal or binary prefixes?

It depends on the context. Storage manufacturers use decimal (KB, MB, GB) because it makes capacities look larger. Memory (RAM) uses binary (KiB, MiB, GiB) because memory addresses are powers of 2. Operating systems traditionally used binary prefixes labelled as decimal, causing confusion. The IEC binary prefixes (kibi, mebi, gibi) were introduced to resolve this.

How many bytes are in a terabyte?

One decimal terabyte (TB) is exactly 1,000,000,000,000 bytes (10^12). One binary tebibyte (TiB) is exactly 1,099,511,627,776 bytes (2^40). The two differ by about 9.95%, which is why a 1 TB drive appears to hold about 931 GiB.

Are the conversions exact?

Yes. Every factor is an exact power of 10 (for decimal prefixes) or an exact power of 2 (for binary prefixes). The only source of error is floating-point rounding, which becomes noticeable for very large numbers but is negligible for practical purposes.

Last updated: July 21, 2026 · Author: HT99 Tools Editorial Team · Reviewed by: HT99 Tools Editorial Team