How to use the data storage converter
- Type a number in the left box and choose the unit you are converting from.
- Choose the unit you want to convert to on the right — the answer appears instantly. You can also type in the right-hand box to convert the other way.
- Press ⇄ to swap the units, or Copy result to paste the answer elsewhere. The table underneath shows your value in every data storage unit at once.
Results are calculated with exact, internationally agreed conversion factors and shown to up to ten significant figures, so they are suitable for homework, cooking, travel, engineering and shopping alike. Bookmark a conversion by adding ?v=10&from=…&to=… to the page address.
Decimal vs binary units
There are two ways to count data sizes, and they cause a lot of confusion:
- Decimal (SI) units — KB, MB, GB, TB — go up in steps of 1,000. 1 GB = 1,000,000,000 bytes. Drive makers, network speeds and most phones use these.
- Binary (IEC) units — KiB, MiB, GiB, TiB — go up in steps of 1,024. 1 GiB = 1,073,741,824 bytes. Windows and RAM sizes use binary values, even though Windows labels them “GB”.
Why does my 1 TB drive show 931 GB?
The drive really holds 1,000,000,000,000 bytes (1 TB, decimal). Windows divides by 1,024 three times and shows the result as “931 GB” — which is actually 931 GiB. Nothing is missing; it’s just a different unit.
| Advertised | Shown in Windows |
|---|---|
| 128 GB | 119 GB |
| 256 GB | 238 GB |
| 512 GB | 476 GB |
| 1 TB | 931 GB |
| 2 TB | 1.81 TB |
| 4 TB | 3.63 TB |
Bits vs bytes
A byte is 8 bits. Internet speeds are quoted in bits per second (Mbps), while file sizes are in bytes (MB). That’s why a 100 Mbps connection downloads at most about 12.5 MB per second.
How big is…?
| Item | Typical size |
|---|---|
| Plain text email | 10–50 KB |
| Smartphone photo (JPG) | 2–5 MB |
| MP3 song (4 min) | 4–8 MB |
| 1 minute of 1080p video | 100–150 MB |
| HD movie (2 hours) | 4–8 GB |
| Modern video game | 50–150 GB |
Need a file smaller? Try the image compressor, PDF compressor or video compressor.
Frequently asked questions
How many MB are in a GB?
1,000 MB in decimal units (or 1,024 MiB in a GiB).
How many GB are in a TB?
1,000 GB (decimal), or 1,024 GiB in a TiB.
What is the difference between MB and MiB?
An MB is 1,000,000 bytes; a MiB is 1,048,576 bytes (1024 × 1024).
How many megabytes per second is 100 Mbps?
About 12.5 MB/s, because there are 8 bits in a byte.