Data Storage Converter

Convert data sizes between bits, bytes, kilobytes, megabytes, gigabytes and terabytes in both decimal (GB) and binary (GiB) units, plus megabits and gigabits.

How to use the data Storage Converter

  1. Enter the value.
  2. Choose the from from the list.
  3. Choose the to from the list.
  4. The result updates instantly as you type. There is no button to press.
  5. Use Copy result to copy the figures, or Copy link to share a link that reopens the data Storage Converter with the same inputs.

How it works

Data sizes come in two families that are easy to confuse. Decimal units (kB, MB, GB, TB) use powers of 1,000, as in the metric system, so 1 GB is exactly 1,000,000,000 bytes. Storage manufacturers, network speeds and macOS use these. Binary units (KiB, MiB, GiB, TiB) use powers of 1,024, which suit how computer memory is addressed, so 1 GiB is 1,073,741,824 bytes. Windows reports file and disk sizes in binary units but labels them "GB".

That mismatch is why a new "1 TB" drive shows up in Windows as about 931 GB: it holds 1,000,000,000,000 bytes, which is 931.3 GiB. Nothing is missing; it's the same number of bytes measured two ways. The gap grows with each step up, from 2.4% at the kilobyte level to almost 10% at the terabyte level.

Network speeds add a third twist: they are measured in bits per second, not bytes, and there are 8 bits in a byte. A "100 Mbps" connection moves at most 12.5 megabytes per second. This converter covers all of these and also estimates how long a file of the given size would take to download at common connection speeds, before protocol overhead.

Formula

1 byte = 8 bits 1 kB = 1,000 B · 1 MB = 1,000² B · 1 GB = 1,000³ B 1 KiB = 1,024 B · 1 MiB = 1,024² B · 1 GiB = 1,024³ B download time (s) = size in bits / speed in bits per second

Example

1 GB = 1,000,000,000 bytes ÷ 1,048,576 = 953.67 MiB, or 0.931 GiB. A "2 TB" drive holds 1.82 TiB, which Windows shows as 1.81 "TB". A 4 GB movie at 100 Mbit/s takes at least 4 × 8,000 ÷ 100 = 320 seconds, about 5 minutes 20 seconds.

Frequently asked questions

Is 1 GB 1,000 MB or 1,024 MB?

Officially, 1 GB = 1,000 MB, and 1 GiB = 1,024 MiB. Some software, notably Windows, uses 'GB' for the binary 1,024-based unit, which causes the confusion.

Why does my hard drive show less space than advertised?

Manufacturers use decimal units (1 TB = 10¹² bytes) while Windows displays binary units (1 TiB = 2⁴⁰ bytes). A 1 TB drive therefore shows as about 931 GB. Formatting also uses a little space.

What is the difference between Mb and MB?

A lowercase b means bits and an uppercase B means bytes. 1 MB = 8 Mb. Internet speeds are usually given in Mbps (megabits per second).