1 kilobyte is precisely 1000 bytes
Published on 11/01/2026
Updated on 15/01/2026
When it comes to computer memory, we usually learn that a kilobyte is 1024 bytes, a megabyte is 1024 kilobytes, and so on. But what if I told you that it's not necessarily true and 1 kilobyte can be 1000 bytes? And what's more, this makes even more sense.
Why do we often say 1 kilobyte = 1024 bytes?
Since computers work in a binary system (base 2), the memory is also addressed in binary. This means it's quite impractical to use memory addresses or produce RAM sticks with memory amounts that are not multiples of powers of 2. From the powers of 2 we chose 1024 (210) as the base order of magnitude, since it's very close to 1000 (2.4% difference) and it's not insanely large. So, in practice we often consider kilo as 1024 (210), mega as 1048576 (220), giga as 1073741824 (230), etc.
Why does 1000 still make more sense?
While binary kilo, mega and giga units are close to their decimal counterparts, some might already notice that the larger are the units, the more is the proportional inaccuracy. In order to illustrate, let's increase the units:
Unit Decimal value Binary value Relative difference Kilo 1000 1024 2.4% Mega 1000000 1048576 ≈ 4.8% Giga 1000000000 1073741824 ≈ 7.3% Tera 1000000000000 1099511627776 ≈ 10% Peta 1015 ~ 1.126 * 1015 ≈ 12.6% Exa 1018 ~ 1.153 * 1018 ≈ 15.3% Zetta 1021 ~ 1.181 * 1021 ≈ 18.1% Yotta 1024 ~ 1.209 * 1024 ≈ 20.9% Ronna 1027 ~ 1.238 * 1027 ≈ 23.8% Quetta 1030 ~ 1.268 * 1030 ≈ 26.8%
For 1 quettabyte the inaccuracy is already larger than a quarter. Even for 1 terabyte the difference is noticeable, around 10%. This problem often happens when hardware manufacturers (such as HDD or SSD) advertise the memory capacity in decimal units while the operating system might show in binary units.
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