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GivenTool

Data storage converter (decimal and binary)

Bytes, kB/MB/GB/TB (decimal) and KiB/MiB/GiB/TiB (binary), plus bits, kilobits, megabits and gigabits.

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Two systems of prefixes are in use for data. Decimal (SI) prefixes step by 1000: 1 kB = 1000 bytes, 1 MB = 1000² bytes, 1 GB = 1000³ bytes. Binary (IEC 80000-13) prefixes step by 1024: 1 KiB = 1024 bytes, 1 MiB = 1024² bytes, 1 GiB = 1024³ bytes. The unit picker lists them in separate groups so you never mix them by accident.

Drive manufacturers, network speeds and macOS use decimal units. Windows and many upload forms compute in binary but still write "KB" and "GB", which is why a 1 TB drive shows as about 931 GB in Windows Explorer: 10¹² bytes ÷ 1024³ = 931.32 GiB. Nothing is missing; the same bytes are counted with a different divisor. The gap grows with each prefix: 2.4% at kilo, 4.9% at mega, 7.4% at giga, 10% at tera.

Network speeds are quoted in bits per second. Divide by 8 to get bytes: a 100 Mbit/s connection moves at most 12.5 MB/s before protocol overhead.

How to use it

  1. Choose the unit you have, checking whether it is decimal (MB) or binary (MiB).
  2. Choose the unit you want and type the size in either box.
  3. Use the table for common drive and memory sizes.

Frequently asked questions

Why does my 1 TB drive show only 931 GB?

The drive holds 1,000,000,000,000 bytes. Windows divides by 1024³ and labels the result GB, giving 931.3; those are really GiB. The capacity is the same.

Is 1 MB 1000 KB or 1024 KB?

By the SI and IEC standards, 1 MB = 1000 kB and 1 MiB = 1024 KiB. In casual use and in Windows, "MB" often means MiB. When a limit matters, assume the smaller figure.

How do I convert Mbps to MB/s?

Divide by 8: 1 byte = 8 bits. 200 Mbit/s = 25 MB/s. Real downloads are a little slower because of protocol overhead.

What does an upload limit of "2 MB" mean?

It may be 2,000,000 bytes or 2,097,152 bytes (2 MiB); sites rarely say which. Aim for a file below 2,000,000 bytes to be safe; the image compressors on this site do that automatically.

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