About this calculator
Both systems are listed.
How to use it
- Enter the value.
- Choose the unit it is in and the unit you want.
- Read the result, or see every unit in the table.
The formula
1 GB = 10⁹ bytes; 1 GiB = 2³⁰ bytes = 1,073,741,824 bytes
- KB, MB, GB, TB
- steps of 1,000
- KiB, MiB, GiB, TiB
- steps of 1,024
- 1 byte
- 8 bits
Worked example
A 128 GB phone
- 128 GB = 128 × 10⁹ bytes.
- = 119.2 GiB, which the phone may show as “119 GB”.
- = 1,024,000 MB.
What the result means
Use decimal units for buying and binary for what the device reports.
Assumptions
- Exact definitions.
Limitations
- Some software labels binary units as GB.
Frequently asked questions
Why does my 1 TB drive show 931 GB?
1 TB = 10¹² bytes = 931 GiB, which the computer labels GB.
How many MB in a GB?
1,000 MB (or 1,024 MiB in a GiB).
How many bits in a byte?
8.
Last reviewed on 3 October 2026. Found a mistake? Tell us.