FreeToolStation

Data Storage Converter

Decimal and binary units together, bits included.

Unit Converters Free, no sign-up Runs in your browser
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Result
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To twelve digits
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Conversion factor
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The other way
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In scientific notation
UnitValueSymbol

About the Data Storage Converter

Data Storage Converter shows both the decimal and the binary families at once, because the confusion between them is the single most common question about file sizes. A kilobyte is 1,000 bytes; a kibibyte is 1,024. The prefixes KB, MB, GB are decimal; KiB, MiB, GiB are binary.

That is why a drive sold as 1 TB shows up as about 931 GB in an operating system. The manufacturer counted 1,000,000,000,000 bytes, which is correct, and the operating system divided by 1,024 three times and labelled the result GB, which is not. Nothing is missing and nobody is cheating: the two are using different units under the same name.

Bits are in the same table because connection speeds are quoted in bits per second while file sizes are in bytes. There are eight bits to a byte, so a 100 Mbit connection downloads at about 12.5 MB per second at best -- a factor of eight that accounts for most complaints about broadband speed.

The page shows its working, not just its answer. Where there is a formula it is printed with your own numbers substituted in, so you can check the result rather than take it on trust -- which is the difference between a calculator you can use for something that matters and one you cannot.

Everything runs inside your browser. What you type is never uploaded, never logged and never stored, and the calculator keeps working if your connection drops after the page has loaded.

Looking for something this does not cover? FreeToolsZone.org is more free browser-based tools, organised by job, and it is worth a look if data storage converter is only part of what you are working on.

How to use the Data Storage Converter

  1. Choose from and toThe fields below change to match what you pick, so only the figures that matter to your case are asked for.
  2. Enter valueDecimals are fine, and thousands separators are accepted and ignored.
  3. Read the result, to twelve digits and conversion factorThe figures update as you type. The Calculate button is there if you would rather press something, but nothing waits for it.
  4. Copy or check the resultCopy the summary with the copy button, or open the table to check it row by row.

Features

  • Shows result, to twelve digits, conversion factor, the other way and in scientific notation together, so you are not running it twice
  • A results table you can read across
  • Updates as you type, with no button to press and no page reload
  • Copy the result in one click
  • Free, no sign-up, and it runs entirely in your browser

Who uses this tool

The data storage converter is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

  • Working out why a 1 TB drive shows as 931 GB
  • Converting a connection speed in Mbps into MB per second
  • Converting between GB and GiB for a server specification
  • Getting a file size in bytes exactly

Frequently asked questions

Why does my 1 TB drive show 931 GB?

Because the drive holds 10^12 bytes and the operating system divides by 1,024 three times while still writing GB. In correct units it is 931 GiB, which is exactly 1 TB.

What is the difference between Mb and MB?

A lowercase b is bits, an uppercase B is bytes. There are eight bits to a byte, so 100 Mb is 12.5 MB.

Which units should I use?

KiB, MiB and GiB when you mean powers of 1,024, and KB, MB, GB when you mean powers of 1,000. The binary prefixes exist precisely to remove the ambiguity.

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Checked and rebuilt on 2026-10-14. The method this calculator uses is described in the section above, and corrections go through the contact page.