File Size Converter
Convert between bytes, kilobytes, megabytes, gigabytes and terabytes — and their binary equivalents (KiB, MiB, GiB, TiB) — and see why a drive or file can show two different sizes.
1,000 MB
1 GB = 1,000 MB
1 GB in every unit
Decimal (SI) — 1 KB = 1,000 bytes
| Bits | 8,000,000,000 |
| Bytes | 1,000,000,000 |
| Kilobytes (KB) | 1,000,000 |
| Megabytes (MB) | 1,000 |
| Gigabytes (GB) | 1 |
| Terabytes (TB) | 0.001 |
| Petabytes (PB) | 0.000001 |
Binary (IEC) — 1 KiB = 1,024 bytes
| Kibibytes (KiB) | 976,562.5 |
| Mebibytes (MiB) | 953.6743 |
| Gibibytes (GiB) | 0.931323 |
| Tebibytes (TiB) | 0.000909495 |
| Pebibytes (PiB) | 8.8818e-7 |
Why does my 1 TB drive show as 931 GB? Drive makers use decimal units (1 TB = 1,000,000,000,000 bytes). Windows divides by 1,024 instead but still labels the result "GB", so the same drive appears as about 931 GB. macOS has used decimal units since 2009, so it shows the full 1 TB.
Everything you enter is processed in your browser and isn't sent to our servers.
How to use file size converter
- 1Enter a size.
- 2Choose the unit you're converting from and the unit you want.
- 3Read the result, or check the tables for the size in every unit at once.
- 4Use the swap button to reverse the conversion.
About this tool
There are two systems for storage units. Decimal (SI) units use powers of 1,000: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes. Binary (IEC) units use powers of 1,024: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes, 1 GiB = 1,073,741,824 bytes. The difference grows with each step — about 2.4% at kilo, 7.4% at giga and 10% at tera.
Example: a drive sold as 1 TB holds 1,000,000,000,000 bytes. Windows divides by 1,024 three times but labels the result “GB”, so it shows about 931 GB. That's the same capacity, just a different unit — nothing is missing. macOS and most drive makers use decimal units.
Memory (RAM) is still commonly described in binary units even when labelled “GB”: 16 GB of RAM is 16 GiB. Network speeds use bits rather than bytes — divide megabits per second by 8 to get megabytes per second.
Frequently asked questions
Officially 1 KB is 1,000 bytes and 1 KiB is 1,024 bytes. In practice some software, including Windows, still uses “KB” to mean 1,024 bytes, which is why sizes can differ between systems.