Hex Calculator

Hex Calculator does arithmetic directly on hexadecimal numbers and converts the result into decimal, binary and octal. A 0x prefix is accepted and ignored, as are spaces and colons, so a MAC address or a byte sequence copied from a dump can be pasted in without cleaning it up first.

Hexadecimal is base sixteen, using 0 to 9 and then A to F for the values ten to fifteen. Its usefulness comes from a single fact: sixteen is two to the fourth, so one hex digit is exactly four bits and two hex digits are exactly one byte. That makes hex a compact, lossless shorthand for binary, which is why colour codes, memory addresses, hashes and permission masks are all written in it.

The bytes figure is often the one that matters. 0xFF is one byte, 0x1AF1 is two, and knowing where a value crosses a byte boundary tells you whether it fits in the field you are putting it in. Division gives a quotient and a remainder, matching integer division in hardware, with the exact decimal value listed as well.

The page shows its working, not just its answer. Where there is a formula it is printed with your own numbers substituted in, so you can check the result rather than take it on trust -- which is the difference between a calculator you can use for something that matters and one you cannot.

Everything runs inside your browser. What you type is never uploaded, never logged and never stored, and the calculator keeps working if your connection drops after the page has loaded.

• Shows result in hex, in decimal, in binary, in octal and bytes needed together, so you are not running it twice
• A results table you can read across
• Prints the formula with your own figures substituted in
• Updates as you type, with no button to press and no page reload
• Copy the result in one click
• Free, no sign-up, and it runs entirely in your browser

The hex calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

• Adding an offset to a memory address
• Working out a hex colour value by hand
• Converting a hex value from a log into decimal
• Checking how many bytes a hex value occupies