Byte Size Converter
Convert between bytes, KB, MB, GB, TB and the binary KiB, MiB, GiB units — plus bits — instantly.
1 GB = 1,000,000,000 bytes
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.