Byte Size Converter
Convert between bytes, KB, MB, GB, TB and the binary KiB, MiB, GiB units, plus bits, instantly.
1 GB = 1,000 MB
A "1 TB" disk shows up as 931 GiB in your file manager: same bytes, different unit.
Decimal (SI, 1000-based)
| Bytes (B) | 0 |
|---|---|
| Kilobytes (kB) | 0 |
| Megabytes (MB) | 0 |
| Gigabytes (GB) | 0 |
| Terabytes (TB) | 0 |
| Petabytes (PB) | 0 |
Binary (IEC, 1024-based)
| Kibibytes (KiB) | 0 |
|---|---|
| Mebibytes (MiB) | 0 |
| Gibibytes (GiB) | 0 |
| Tebibytes (TiB) | 0 |
| Pebibytes (PiB) | 0 |
Bits (network / bandwidth)
| Bits (bit) | 0 |
|---|---|
| Kilobits (kbit) | 0 |
| Megabits (Mbit) | 0 |
| Gigabits (Gbit) | 0 |
| Terabits (Tbit) | 0 |
How it works
Type a size, pick its unit, and every other data unit is recalculated instantly — no Convert button to press. The table shows all three families side by side: decimal units where 1 kB = 1000 bytes (how drive manufacturers and macOS count), binary units where 1 KiB = 1024 bytes (how Windows and RAM are counted), and bits for network speeds where 1 byte = 8 bits. That is why a "1 TB" disk shows up as roughly 931 GiB in your file manager: same bytes, different unit. Values are rounded to six decimals, and very large or very small results switch to scientific notation. Everything is plain JavaScript arithmetic running in your browser — nothing is sent to a server.
Frequently asked questions
How many bytes are in a megabyte?
It depends on the unit family. A decimal megabyte (MB) is exactly 1,000,000 bytes, the definition used by drive manufacturers, network gear and macOS. A binary mebibyte (MiB) is 1,048,576 bytes (1024 × 1024), which is what Windows and most RAM specs mean when they say "MB". This converter shows both at the same time, so you never have to guess which one a number refers to.
What is the difference between MB and MiB?
MB is the decimal (SI) megabyte of 1,000,000 bytes; MiB is the binary (IEC) mebibyte of 1,048,576 bytes, about 4.9% larger. The gap widens with each step: a 1 TB drive holds 1,000,000,000,000 bytes, which your file manager reports as roughly 931 GiB. Nothing is missing. It is just a different unit. Enter a value here and compare the decimal and binary columns side by side.
How do I convert GB to MB?
Type the number of gigabytes in the Size box, pick Gigabytes (GB) as the unit, and read the Megabytes (MB) row. Every unit updates as you type, so 1 GB immediately shows as 1,000 MB, 953.674316 MiB and 8,000 Mbit. Use Copy all values to grab the whole conversion table at once, or Download .txt to save it.