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Byte Conversion Calculator

Byte Conversion Calculator

Convert between digital storage units

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Two different conventions are used for storage units, and mixing them up is the most common source of confusion. Decimal (base-10) units like kilobyte (KB), megabyte (MB) and gigabyte (GB) use powers of 1000 — 1 KB = 1000 bytes. Binary (base-2, "IEC") units like kibibyte (KiB), mebibyte (MiB) and gibibyte (GiB) use powers of 1024 — 1 KiB = 1024 bytes.

Hard drive makers typically advertise decimal (base-10) capacity, while operating systems like Windows often display binary (base-2) values but mislabel them with decimal names (showing "GB" when they mean GiB). That's why a "1 TB" drive shows up as roughly 931 GB in Windows. This tool lets you convert precisely between both systems.

Enter a value, choose your source and target units, and the result updates automatically.

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Quick Reference (from your input)
All conversions use the bit as the internal base unit. Decimal units (KB, MB...) use powers of 1000; binary units (KiB, MiB...) use powers of 1024. Provided by calculator24x7.com

A “1 TB” hard drive showing up as roughly 931 GB in Windows isn’t a manufacturing shortfall, it’s two different, equally valid counting systems disagreeing about what “giga” means. This calculator converts precisely between both.

How to use this byte conversion calculator

  1. Enter a value and select your From unit.
  2. Select your To unit.
  3. Read the converted result instantly, or tap Swap Units to reverse the direction.

What this calculator does

Two different conventions are used for storage units, and mixing them up is the most common source of confusion. Decimal (base-10) units like kilobyte (KB), megabyte (MB), and gigabyte (GB) use powers of 1000, 1 KB equals 1000 bytes. Binary (base-2, “IEC”) units like kibibyte (KiB), mebibyte (MiB), and gibibyte (GiB) use powers of 1024, 1 KiB equals 1024 bytes.

Decimal: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes
Binary: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes, 1 GiB = 1,073,741,824 bytes

Why your “1 TB” drive shows less than 1 TB

Hard drive makers typically advertise decimal (base-10) capacity, since it produces a larger, cleaner-looking number, while operating systems like Windows often display binary (base-2) values but mislabel them with decimal names, showing “GB” when they actually mean GiB. This mismatch is exactly why a “1 TB” drive shows up as roughly 931 GB in Windows, the drive genuinely has 1,000,000,000,000 bytes, but Windows is dividing that figure using 1024-based math and calling the result GB instead of the more accurate GiB.

Frequently asked questions

Why does my 1 TB hard drive show up as only 931 GB in Windows?

The drive manufacturer uses decimal (1000-based) units to advertise capacity, giving exactly 1,000,000,000,000 bytes, while Windows calculates and displays using binary (1024-based) math but mislabels the result with decimal unit names, producing the smaller-looking 931 GB figure for the identical amount of storage.

What’s the difference between KB and KiB?

KB (kilobyte) is the decimal unit equal to 1,000 bytes, while KiB (kibibyte) is the binary unit equal to 1,024 bytes. Many systems display KiB values but label them “KB,” which is the root of most storage-size confusion.