Numbers & bits
Number base converter
Convert whole numbers between binary, octal, decimal and hexadecimal, with the place values and the division steps shown.
In binary: 0111 1110 1010
Bitwise calculator (AND, OR, XOR, shifts)
AND, OR, XOR, NOT and bit shifts on 8-, 16- or 32-bit numbers, with the bits lined up and the two’s-complement value.
Result (unsigned): 8
Networks & security
IP subnet calculator
Network address, broadcast, usable host range, subnet mask and host count for any IPv4 address and prefix (CIDR).
Network address: 192.168.1.128
Password strength calculator
Entropy in bits and the time to guess a password or passphrase by brute force. Nothing you type is sent: you enter only the length and character set.
Entropy: 78.8 bits
Hardware & screens
RAID capacity calculator
Usable space, fault tolerance and storage efficiency for RAID 0, 1, 5, 6 and 10.
Usable capacity: 24 TB
Screen size & PPI calculator
Pixel density (PPI), dot pitch and the real width and height of a screen from its resolution and diagonal.
Pixel density: 163.2 PPI
Aspect ratio calculator
Find the aspect ratio of an image, video or screen, or the new height for a width while keeping the same shape.
Aspect ratio: 16 : 9
Text & encoding
Base64 encoder & decoder
Turn text into Base64 and back, with each byte’s path to a Base64 letter shown bit by bit.
Hi → SGk=
URL encoder & decoder
Percent-encode text for links and query strings, or turn %20-style codes back into text, character by character.
a b&c → a%20b%26c
HTML entity encoder & decoder
Escape <, >, & and quotes so text shows safely in a web page, or turn &-style entities back into characters.
<b> → <b>
Unicode escape converter
Write characters as \u2615-style escapes for code, or turn escapes back into text, with each character’s code point.
☕ → \u2615
JSON string escaper
Turn any text into a valid JSON string, with quotes, backslashes and line breaks escaped, or unescape a JSON string back into text.
He said "hi" → "He said \"hi\""
JWT decoder
Read the header and payload of a JSON Web Token, with issue and expiry times turned into dates.
eyJhbGci… → header + payload