Tech & Media Calculators

Bits, bytes and the two kinds of gigabyte

Nearly every confusing number in computing comes from one of two ambiguities. The first is bits against bytes: network speeds are quoted in bits per second and file sizes in bytes, and there are eight bits to a byte — so a 100 Mbps connection downloads at about 12.5 MB/s, not 100. The Mbps to MB converter does that division and gives the transfer time, and the bandwidth calculator extends it to a file of any size.

The second is decimal against binary. A gigabyte is 10⁹ bytes to a drive manufacturer and 2³⁰ bytes to most operating systems, a difference of about 7% that grows with scale — which is why a 1 TB drive reports as roughly 931 GB. The data storage converter shows both columns at once and never silently mixes them, because the mixing is the bug.

Screens, media and networks

The aspect ratio calculator simplifies a resolution to its lowest terms and resizes while keeping proportions exact, which is what stops an image being stretched by a rounded-off dimension. The file size calculator works in both directions: size from bitrate and duration, or the bitrate needed to hit a target size — the calculation behind every export setting in a video editor.

On the network side, the IP subnet calculator turns a CIDR prefix into the network address, broadcast address, usable host range and mask, and the base converters translate between hexadecimal, decimal, binary and octal with the bit weights shown so the answer is checkable rather than merely asserted.

The password entropy calculator measures a password the way an attacker would: bits of entropy given the character set and length, and the time a brute-force attempt would take at plausible rates. Length dominates character variety, and the tool makes that visible. Nothing you type into it is transmitted — like everything here, it runs entirely in your browser.