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KB, MB, GB, and TB Explained: Data Storage Units

Unit Converters · By DailyTools Editorial Team · July 30, 2026 · 2 min read

Storage labels look simple until 1,000-based and 1,024-based units produce different numbers. Here is what to check.

Illustration comparing bytes, kilobytes, megabytes, gigabytes, and terabytes

Unit Converters

Digital storage is measured in bytes and larger units built from bytes. You see these labels when checking file sizes, phone storage, download limits, memory cards, and cloud plans. The confusing part is that some systems use groups of 1,000 while others use groups of 1,024.

The basic storage ladder

  • 1 byte is commonly eight bits.
  • 1 kilobyte (KB) is often shown as 1,000 bytes, but some systems use 1,024 bytes.
  • 1 megabyte (MB) is roughly a million bytes in decimal notation.
  • 1 gigabyte (GB) is roughly a billion bytes in decimal notation.
  • 1 terabyte (TB) is roughly a trillion bytes in decimal notation.

Why your device may show less space than the box

A storage manufacturer may describe a drive using decimal units, where 1 GB equals 1,000 MB. An operating system may display the same capacity using 1,024-based calculations. The physical drive has not lost space; the labels and calculation convention differ. Formatting, system files, and reserved storage can also reduce the usable space you see.

Binary and decimal units

For technical precision, binary units are often written as KiB, MiB, GiB, and TiB, where each step is 1,024 times the previous unit. Everyday products do not always use that notation consistently. Before comparing two values, check whether the source is using decimal or binary factors.

A conversion example

Using the 1,024-based convention, 5 GB equals 5 × 1,024 MB, or 5,120 MB. Using decimal factors, 5 GB equals 5,000 MB. The Data Storage Converter on this site uses 1,024-based factors consistently, so its result should be compared with sources using the same convention.

Practical checks before you convert

  • Confirm whether the source means bits (b) or bytes (B); eight bits equal one byte.
  • Use the same decimal or binary convention on both sides of a comparison.
  • Treat a converted file size as an estimate of capacity, not a guarantee of available disk space.
  • For download time, account for the connection speed and overhead separately.

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