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Data size converter

Convert MB and MiB without pretending 1024 and 1000 are the same.

This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.

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What this tool does

The base is the byte of eight bits. SI kilobytes are 1000 bytes. IEC kibibytes are 1024 bytes. Drive stickers often use SI; some operating systems still print GiB as GB. ConvertPass shows both and will not pick a side in silence.

How to use it

  1. Enter the size.
  2. Pick SI or IEC units from the labelled menu.
  3. Convert and copy the JSON.

Supported input

  • A number and two data-size units from the menu

Output

  • JSON with the converted size plus every other unit in the family

Privacy

This tool processes files and text locally in your browser. Your content is not uploaded or stored by this site.

ConvertPass does not include your input in analytics, URLs, or error reports. Encoding: Decimal numbers / byte. Limit: A single size (4.0 KB).

Limitations

  • This counts bytes, not filesystem clusters, RAID parity, or video bitrate over time. Use the bitrate calculator for bits per second over a duration.
  • A ‘KB’ written on a 1990s MS-DOS box may mean 1024. Read the IEC label here.
  • Negative sizes are refused.

Example

Input
1 GiB → GB
Output
{
  "result": 1.073741824,
  "formatted": "1 GiB = 1.073741824 GB"
}

Troubleshooting

A 1 TB drive shows about 931 GB in the OS
The sticker used SI terabytes (10^12). The OS often reports gibibytes or a mix. Convert 1 TB SI to GiB here.

FAQ

Is a kilobyte 1000 or 1024 bytes?

Here, kB is 1000 and KiB is 1024. If a vendor wrote KB, check which system they meant.

Are bits and bytes both here?

Yes. Eight bits make one byte. Network speeds in Mbit are bits; file sizes in MB are usually bytes.

Can I convert a video bitrate to a file size?

Use the duration and file size tool in Video. This page only converts a static quantity of data.

Why not hide IEC names?

Hiding them is how 931 GB surprises happen. The menu spells SI and IEC out.

Related tools

Related formats

Last reviewed 16 August 2026. Report a problem. Reports do not include your input.