Byte Conversion Calculator
This calculator converts any value between the units used to measure digital storage and data - bits, bytes, kilobytes, megabytes, gigabytes, terabytes and petabytes. It matters because there are two different definitions of these units in everyday use: operating systems, RAM specifications and file managers use the binary system, where each step up is a multiple of 1,024, while hard drive manufacturers, SSD makers and internet providers use the decimal system, where each step is a multiple of 1,000. This is why a "1 TB" drive shows as roughly 931 GiB in Windows, and why file sizes on screen never quite match what the box promised. You enter a value and choose which unit it is currently in, from bits through to petabytes in either system, then set your preferred display precision and choose fixed decimal or scientific notation for very large or small numbers. The calculator instantly returns the equivalent in bits, bytes, and megabytes in both binary and decimal form as headline results, plus full conversion tables covering every unit in the binary (base 1024) and decimal (base 1000) systems side by side. Use it to check download times against advertised broadband speeds, work out the real usable storage on a new drive, convert RAM or file sizes for a spec sheet, or simply settle an argument about what a gigabyte actually is.
1. Enter Value
2. Options
Binary System (Base 1024)
| Unit | Symbol | Value | Bytes |
|---|
Decimal System (Base 1000)
| Unit | Symbol | Value | Bytes |
|---|
How Byte Conversion Works
Digital storage is measured in bytes, where each byte contains 8 bits. A bit is the smallest unit of digital information and can hold either a 0 or a 1. All file sizes, memory capacities, and storage devices are ultimately measured in multiples of bytes.
There are two systems for expressing byte multiples, which differ in what "kilo", "mega", and "giga" mean:
Binary System (Base 1024)
Computers work in base 2, so the natural multiplier is 2 to the power of 10 = 1,024. Operating systems (Windows, macOS, Linux), RAM specifications, and many file managers use this system. The IEC introduced specific names to remove ambiguity: kibibyte (KiB), mebibyte (MiB), gibibyte (GiB) and so on, though many people still say "kilobyte" or "megabyte" when they mean the binary values.
| Unit | IEC Symbol | Bytes | In bytes |
|---|---|---|---|
| Bit | b | 1/8 | 0.125 |
| Byte | B | 1 | 1 |
| Kilobyte (Kibibyte) | KB / KiB | 1024^1 | 1,024 |
| Megabyte (Mebibyte) | MB / MiB | 1024^2 | 1,048,576 |
| Gigabyte (Gibibyte) | GB / GiB | 1024^3 | 1,073,741,824 |
| Terabyte (Tebibyte) | TB / TiB | 1024^4 | 1,099,511,627,776 |
| Petabyte (Pebibyte) | PB / PiB | 1024^5 | 1,125,899,906,842,624 |
Decimal System (Base 1000)
Hard drive manufacturers, solid-state drive (SSD) manufacturers, and network equipment vendors use the SI (International System of Units) decimal prefixes where 1 kilo = 1,000. This is why a "1 TB" drive shows as roughly 931 GiB in Windows: Windows uses binary GiB (1,073,741,824 bytes) while the manufacturer counts in decimal GB (1,000,000,000 bytes).
| Unit | Symbol | Bytes | In bytes |
|---|---|---|---|
| Kilobyte | kB | 1000^1 | 1,000 |
| Megabyte | MB | 1000^2 | 1,000,000 |
| Gigabyte | GB | 1000^3 | 1,000,000,000 |
| Terabyte | TB | 1000^4 | 1,000,000,000,000 |
| Petabyte | PB | 1000^5 | 1,000,000,000,000,000 |
Worked Example: 1 Byte
Starting with 1 byte (the default), the calculator converts to all units as follows:
- Bits: 1 x 8 = 8 bits
- Bytes: 1 byte
- Kilobytes (binary): 1 / 1,024 = 0.0010 KB
- Megabytes (binary): 1 / 1,048,576 = 0.0000 MB
- Kilobytes (decimal): 1 / 1,000 = 0.0010 kB
- Megabytes (decimal): 1 / 1,000,000 = 0.0000 MB
These match the default output of the calculator above with precision set to 4 decimal places.
Common Uses
- Internet speeds: ISPs quote speeds in megabits per second (Mbps). To find your file download speed in MB/s, divide by 8. A 100 Mbps connection downloads at up to 12.5 MB/s.
- Storage capacity: Hard drives and SSDs use decimal gigabytes. A 1 TB drive holds approximately 931 GiB as shown by Windows.
- RAM: Memory is always specified in binary gibibytes (GiB), though usually labelled GB.
- File sizes: Operating systems typically report file sizes in binary kibibytes or mebibytes (shown as KB or MB).
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Method and sources: Binary prefix values follow IEC 80000-13:2008 (kibibyte = 2^10 bytes, mebibyte = 2^20 bytes, etc.). Decimal prefix values follow the International System of Units (SI) where kilo = 10^3, mega = 10^6, and so on. The bit-to-byte relationship (1 byte = 8 bits) is defined by the standard ASCII/Unicode encoding convention.
This calculator converts between common digital storage units using standard binary (base-1024) and decimal (base-1000) systems. Results are rounded to the selected precision. For very large or very small values, use scientific notation mode to see full precision.