How to use the Data Storage Converter
- Enter the size, such as 1 for a 1 TB drive or 500 for a 500 MB file.
- Choose the unit you have. Bits, decimal bytes (KB, MB, GB) and binary bytes (KiB, MiB, GiB) are grouped separately.
- Choose the unit you want and read the result.
- Compare the decimal and binary figures in the full list, and click any value to copy it.
Features
- Decimal (SI) and binary (IEC) prefixes side by side
- Bits and bytes, for both storage and network speeds
- From single bits to petabytes and pebibytes
- Explains the 1,000 versus 1,024 difference
- Every unit at once with one-click copy
- Clickable table of common conversions
Bits and bytes
A bit is a single binary digit, a 0 or a 1. A byte is a group of eight bits, enough to store one character of plain English text. File sizes and storage are measured in bytes (capital B), while network speeds are usually quoted in bits per second (lowercase b). That is why a 100 Mbps connection downloads at most about 12.5 megabytes per second: divide by eight, then expect a little less because of protocol overhead.
Two meanings of “kilo”
In the SI system, kilo means 1,000, mega a million and giga a billion. Early computer memory came in powers of two, and 1,024 bytes was close enough to 1,000 that engineers called it a kilobyte too. As capacities grew, the gap widened from 2.4% at the kilo level to almost 10% at tera. To end the confusion, the International Electrotechnical Commission introduced binary prefixes in 1998: kibi (KiB, 1,024 bytes), mebi (MiB, 1,024² bytes), gibi (GiB, 1,024³ bytes) and tebi (TiB, 1,024⁴ bytes).
Who uses which
- Drive and USB stick makers label capacity in decimal units: 1 TB means 1,000,000,000,000 bytes.
- macOS has reported file and disk sizes in decimal units since 2009.
- Windows calculates in binary units but displays them with decimal labels, so a GiB figure appears as “GB”.
- RAM is built in powers of two, so a “16 GB” memory module actually holds 16 GiB.
Worked example: the “missing” space on a new drive
A 1 TB drive holds 1,000,000,000,000 bytes. Windows divides by 1,024³ = 1,073,741,824 and shows 931.32, labeled GB. Nothing is missing; the same number of bytes is being described in a bigger unit. Formatting and recovery partitions then take a little more.
A second example: a 4.7 GB DVD holds 4.7 billion bytes, which is 4.38 GiB. And a 250 MB upload limit is 238.42 MiB.
Decimal versus binary at a glance
| Decimal | Bytes | Binary | Bytes | Difference |
|---|---|---|---|---|
| 1 KB | 1,000 | 1 KiB | 1,024 | 2.4% |
| 1 MB | 1,000,000 | 1 MiB | 1,048,576 | 4.9% |
| 1 GB | 10⁹ | 1 GiB | 1,073,741,824 | 7.4% |
| 1 TB | 10¹² | 1 TiB | 1,099,511,627,776 | 10.0% |
| 1 PB | 10¹⁵ | 1 PiB | 1,125,899,906,842,624 | 12.6% |
Tips
When a website limits uploads to “2 MB”, it may mean either 2,000,000 or 2,097,152 bytes, so aim a little under. To make files fit, shrink them with the Image Compressor or Compress PDF. If you work with raw bits and hex values, the Number Base Converter helps.
Frequently asked questions
Is 1 GB equal to 1,000 MB or 1,024 MB?
In the SI (decimal) system, 1 GB is 1,000 MB. The binary unit, 1 GiB, is 1,024 MiB. Windows uses the binary value but writes it as GB, which causes the confusion.
Why does my 1 TB drive show only 931 GB?
The maker counts 1 TB as 10¹² bytes. Windows divides by 1,024³ and reports 931.32, labeled GB, though it is really GiB. The bytes are all there.
What is the difference between Mb and MB?
Mb is megabits and MB is megabytes. One byte is 8 bits, so 100 Mb is 12.5 MB.
What is a GiB?
A gibibyte is 1,073,741,824 bytes (1,024³). It is the binary counterpart of the gigabyte and about 7.4% larger.
How many bytes are in a kilobyte?
1,000 bytes in the decimal (SI) definition. Some software still uses 1,024 bytes, which is properly called a kibibyte (KiB).