Free online data storage converter. Instantly convert between bits, bytes, kilobytes (kB), kibibytes (KiB), megabytes (MB), mebibytes (MiB), gigabytes (GB), gibibytes (GiB), terabytes, tebibytes, petabytes and pebibytes. Shows the exact difference between decimal and binary units — everything runs in your browser.
Converting file sizes or storage capacities takes three quick steps — there is nothing to install:
This is the single most common source of confusion when converting data sizes, and the two systems are deliberately offered side by side:
The output area keeps you grounded in what actually happened:
In the early days of computing, storage was measured in powers of two because memory chips are addressed in binary. A 'kilobyte' naturally meant 1024 bytes — 2 to the power of 10, close to the decimal thousand. As storage devices grew and the general public started buying disk drives and memory cards, manufacturers adopted the decimal definition (1000 bytes) because larger numbers on the packaging sell better. The result was decades of inconsistency: a 1.44 MB floppy held 1,474,560 bytes, which is 1440 KiB but only 1.47 MB — yet everyone called it 1.44 MB. In 1998 the International Electrotechnical Commission introduced unambiguous prefixes: kilo-, mega-, giga- for powers of 1000 and kibi-, mebi-, gibi- for powers of 1024. Adoption has been slow — engineers say 'kibibyte' with a straight face, marketing departments never will — so the confusion is likely to persist. This converter sidesteps the entire argument by listing both systems explicitly.
One byte is eight bits, so converting between them simply multiplies or divides by eight. This matters constantly in networking. Internet speeds are advertised in megabits per second (Mbps) while file sizes are measured in megabytes (MB) — a '100 Mbps' connection actually transfers a maximum of 12.5 MB per second. Downloading a 1 GB file on such a line therefore takes at least 80 seconds in theory. Forgetting the factor of eight is one of the most common mistakes when estimating transfer times, and it is routinely exploited by broadband marketing. This converter includes the bit as a first-class unit so you can move between network speeds and file sizes without arithmetic slips.
A megabyte (MB) is exactly 1,000,000 bytes, based on powers of ten. A mebibyte (MiB) is exactly 1,048,576 bytes, based on powers of two (1024 × 1024). The mebibyte is about 4.86% larger. Storage manufacturers use decimal megabytes, while operating systems and memory sizes typically use binary mebibytes. This converter supports both and clearly labels them so you always know which one you are working with.
The drive is sold using decimal gigabytes (500 × 10^9 = 500,000,000,000 bytes), but Windows displays capacity in binary gibibytes (500,000,000,000 ÷ 1,073,741,824 ≈ 465.7 GiB), which it labels as 'GB'. No storage is missing — it is purely a difference in the unit definition. macOS changed to decimal units in 2009, so it now reports roughly 500 GB for the same drive.
Exactly eight. A byte is eight bits, so 1 byte = 8 bits and 1 bit = 0.125 bytes. This factor of eight is essential when converting between network speeds (usually quoted in megabits per second) and file sizes or download times (usually quoted in megabytes).
It supports the bit, the byte, and both decimal and binary multiples up to the exabyte scale of storage: kB, KiB, MB, MiB, GB, GiB, TB, TiB, PB and PiB. Any unit converts to any other, so you can move freely between metric-prefixed and binary-prefixed values.
Yes. Decimal units use exact powers of 1000 and binary units use exact powers of 1024, so every conversion is mathematically exact. The only rounding that occurs is in the on-screen display, where the result is formatted to a sensible number of digits for readability. Very large or very small values are shown in scientific notation.
It is completely free and requires no sign-up. All conversion happens locally in your browser with JavaScript, so no value you enter is ever uploaded. Once the page has loaded it also works offline, which makes it handy on a machine with no internet connection.
Indirectly, yes. Convert your file size to bits using a decimal megabit or gigabit unit, then divide by your connection speed in bits per second. For example a 1 GB file equals 8 gigabit (8 × 10^9 bits); at 100 Mbps that is 80 seconds. Remember that network speeds are quoted in bits, not bytes, which is why the bit is included as a unit here.