File size converter
Type a size, choose the units and see it in bytes, kilobytes, megabytes, gigabytes and terabytes, in both the 1,000 and the 1,024 system.
Free · no signup Runs in your browser
How do I convert MB to GB?
In the decimal system that disk makers and most websites use, 1 GB is 1,000 MB, so divide megabytes by 1,000. In the binary system that computers use internally, 1 GiB is 1,024 MiB, so divide mebibytes by 1,024. A 4,096 MB file is 4.096 GB or exactly 4 GiB. The converter shows both, so you can see where the difference comes from.
Why 1 GB is not always 1,000 MB
The prefixes kilo, mega and giga mean 1,000, 1,000,000 and 1,000,000,000 in the metric system, and drive makers, mobile plans and websites use them that way. Operating systems and memory, however, work in powers of 2, where 1,024 is the natural step, and some of them have long labelled that with the same letters (KB, MB, GB). The standards body resolved the confusion with separate names: kibibyte (KiB) is 1,024 bytes, mebibyte (MiB) is 1,024 KiB and gibibyte (GiB) is 1,024 MiB.
That explains why a 1 TB drive shows up as about 931 GB in an operating system that counts in binary: 1,000,000,000,000 bytes is 931.3 GiB. Nothing is missing; the two systems are using different units with similar labels.
It runs in your browser. Nothing you type is sent anywhere, and there is no sign-up.
Common sizes
Rough sizes people look up. A phone photo is a few megabytes, a song a few megabytes, a one-hour HD video one to several gigabytes, and a game install tens of gigabytes. An email attachment limit of 25 MB means 25,000,000 bytes in the decimal system. Your internet speed in megabits per second is a different unit again: 8 bits make a byte, so 100 Mbps is 12.5 MB per second at best.
Mistakes it helps you avoid
- Mixing megabits (Mb) with megabytes (MB): a byte is 8 bits.
- Expecting a 1 TB drive to show 1,000 GB in a binary system.
- Using 1,000 for memory sizes and 1,024 for drive sizes.
- Reading an upload limit in the wrong system.
How the conversion works
Every unit is first turned into a base unit, then into the unit you want.
bytes = value × (bytes in your unit)result = bytes ÷ (bytes in the unit you want)kB, MB, GB, TB use 1,000 per step; KiB, MiB, GiB, TiB use 1,024 per step; 1 byte = 8 bits
The decimal prefixes are SI. The binary names (kibi, mebi, gibi, tebi) were set by the IEC and are described by NIST. Results are rounded for display only.
Example: a 1 TB drive in GiB
A 1 TB drive is sold in decimal units, and you want to know what a binary operating system will show.
- Bytes1 TB = 1,000,000,000,000 bytes
- To GiB1,000,000,000,000 ÷ 1,073,741,824 = 931.32
1 TB = 931.32 GiB
No space is missing: it is a different unit.
Terms on this page
- Kibibyte (KiB)
- 1,024 bytes.
- Kilobyte (kB)
- 1,000 bytes in the SI system.
Common questions
Is 1 GB 1,000 MB or 1,024 MB?
It is 1,000 MB in the decimal (SI) system. The binary unit is the gibibyte, and 1 GiB is 1,024 MiB.
Why does my 1 TB drive show less?
Because it holds 1,000,000,000,000 bytes, which a binary system counts as 931 GiB.
How many bytes are in a megabyte?
1,000,000 bytes in the decimal system and 1,048,576 in a mebibyte.
How many bits are in a byte?
Eight.
Is anything I type sent to a server?
No. The conversion happens in your browser.
Where these numbers come from
- NIST — Prefixes for binary multiples Why 1 KiB is 1,024 bytes and 1 kB is 1,000 bytes.
- NIST — Guide for the Use of the International System of Units, Appendix B.8 (conversion factors) The exact definitions used here, such as 1 inch = 2.54 centimetres and 1 pound = 0.45359237 kilograms.
Last verified 2026-10-25 The method on this page is checked against the sources above at least once a year. Spotted something out of date? Tell us and we will fix it.
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