The File Size Converter takes one value, one unit and one mode, and prints the same quantity in all six units at once: bytes, then the next five steps up, whether you are in decimal mode (KB, MB, GB, TB, PB) or binary mode (KiB, MiB, GiB, TiB, PiB). It answers a single question, what is this file in the other units, and every row of the result table is derived from one byte count. All of the arithmetic happens in the browser with no backend and no API call. Start at the File Size Converter and leave the placeholders alone: type 10, keep TB selected, decimal mode on.
The one byte count
The first step is one multiplication: the value you typed is multiplied by the factor of the unit you selected, and the product is the byte count. Ten TB in decimal mode is 10 times 1000000000, a byte count of 10000000000000. The second step divides that single byte count by the factor of every other unit, six divisions in all, and each quotient becomes one row. No value is converted to a second value and then to a third; every row reads the same bytes from a different angle. The same byte-count logic is what the Image Info tool applies when it reads the size of a real image file.
Decimal and binary bases
The two modes differ only in the step size between units. Decimal mode steps by 1000, so a KB is 1000 bytes and a GB is 1000 times 1000 times 1000 bytes. Binary mode steps by 1024, so a KiB is 1024 bytes and a GiB is 1024 cubed, which is 1073741824 bytes. Toggling the mode keeps your selection valid by mapping the chosen unit to its positional counterpart, TB to TiB, MB to MiB, so the same number now means a slightly different byte count. The difference compounds three steps up: one GiB is about 7 percent larger than one GB. The bit-level picture behind all of this, bits against bytes, is covered by the text to binary guide.
Running the example
Type 10 with TB selected in decimal mode. The rows print as follows: 10000000000000 bytes, 10000000000 KB, 10000000 MB, 10000 GB, 10 TB, and 0.01 PB. Switch to binary mode, and the selected unit becomes 10 TiB: 10995116277760 bytes, 10737418240 KiB, 10485760 MiB, 10240 GiB, 10 TiB, and 0.009313 PiB. The decimal and binary rows disagree on every step above bytes, because their factors differ, and the disagreement grows with each step you climb.
The reference table
Below the table the tool lists six everyday files with their fixed byte counts: a text email at 50000 bytes, a photo at 3000000, an MP3 song at 5000000, a 1080p movie at 1500000000, an OS installer at 4000000000, and a game at 50000000000. Each row shows the count expressed in GB in decimal mode, 0.05, 3.00, 5.00, 1.50, 4.00 and 50.00, or in GiB in binary mode, where the movie reads 1.40, the installer 3.72, and the game 46.57. The table exists so you can recognize an order of magnitude the moment you read a size. If you want the size to actually move, the Image Converter re-encodes the file into another format and the byte count follows the new format.
How the numbers are printed
The print rule keeps the table readable across ten orders of magnitude. A zero prints as a bare 0. A value of 1 or larger prints with grouping and at most 2 decimals, so the GB row of the example reads 10000. A value smaller than 1 prints with 4 significant digits, which is why the PB row of the same example reads 0.01 while the PiB row of the binary run reads 0.009313. The rule is the same in both modes; only the underlying byte count changes.
What it is not
The File Size Converter is not a compressor. It re-expresses a size; it never touches the bytes. If you want the file itself to shrink, the Image Compressor reduces an image, the CSS Minifier trims a stylesheet, and the JS Minifier trims a script, and each of those changes the true byte count. It is also not a file inspector. For the real metadata of one image, dimensions, format and size, the Image Info guide walks through reading a specific file.