Bits, bytes and the 1000 versus 1024 question
A bit is the smallest unit of digital data, a single 0 or 1. A byte is eight bits. Larger units are built on top of the byte: kilobytes, megabytes, gigabytes and terabytes.
There are two ways to scale those larger units. The decimal (SI) approach multiplies by 1000 at each step, so one kilobyte is 1000 bytes. The binary approach multiplies by 1024, which is a power of two that suits how memory is addressed. Storage makers and many operating systems quote decimal sizes, while some software and memory specs use binary sizes.
This tool uses decimal factors of 1000. One kilobyte is 1000 bytes, one megabyte is 1000 kilobytes, and so on. It does not offer 1024-based units such as KiB, MiB or GiB.
When you need to convert storage sizes
Common cases include working out whether a file fits on a drive, estimating how many photos fit on a memory card, or comparing a plan's monthly data allowance with the size of files you want to send.
It also explains a familiar puzzle: a drive sold as 1 terabyte can show a smaller number in an operating system that counts in 1024-based units. The device maker counted 1,000,000,000,000 bytes, while the system divides by larger steps, so the displayed figure looks lower even though nothing is missing.
Converting bits to bytes is useful for network speeds, which are typically quoted in bits, while file sizes are in bytes. Eight bits make one byte, so you can see how long a transfer might take.
How to convert data sizes with this tool
- Enter a number in the box under From. It starts at 1.
- Choose your unit in the From drop-down: Bits, Bytes, Kilobytes, Megabytes, Gigabytes or Terabytes.
- Choose the target unit in the To drop-down from the same six options.
- Read the result in the To box. It updates as you type.
The tool opens on Bits to Bytes, so the first thing you will see is 0.125. Results are rounded to six decimal places, and everything is computed in your browser.
Worked examples and limits
Since the factors are decimal, the maths is easy to check: 1 gigabyte is 1000 megabytes, 1 terabyte is 1000 gigabytes, 5 megabytes is 5,000,000 bytes, and 1 byte is 8 bits.
If you need the number your operating system would show in binary units, divide the byte count by 1024 for each step instead of by 1000. That gives a slightly smaller result, around 7 percent lower at the gigabyte level, which is why advertised and displayed capacities differ. Treat this converter's output as the decimal figure.
Very large or very small conversions may be rounded at six decimals, so a result like a few bits expressed in terabytes can show as 0. Convert into a nearer unit for a readable answer. If you are comparing file sizes while preparing uploads, the Unit Converter Hub offers other categories in the same style.