Developer Calculator

A programmer's calculator does two jobs a regular one can't: it shows the same number in binary, octal, decimal, and hex simultaneously, and it does bitwise math inside a fixed register width the way a real CPU does — wrapping, sign bits and all. This tool does both, entirely in your browser, using arbitrary-precision integers so even 64-bit values stay exact.

Reading a value in every base

Set the input base (binary, octal, decimal, or hex), then type a value. Every field updates at once. A few input conveniences:

• Underscores are ignored, so 1_000_000 and 0xFF_FF are fine — handy for making long binary strings readable.
• A leading - is accepted for negative decimals.
• A matching base prefix is stripped automatically: 0x in hex mode, 0b in binary, 0o in octal.

Invalid characters for the chosen base (a 2 in binary mode, a g in hex) simply show an "invalid" note rather than guessing.

Why the bit width changes the answer

Below the conversions, pick a bit width — 8, 16, 32, or 64. This is the size of an imaginary register the value is poured into, and it decides the signed interpretation via two's complement. The classic example: enter 255. At 32-bit it reads 255 signed and 255 unsigned. Switch to 8-bit and the unsigned view stays 255, but the signed view becomes -1 — because in a single byte, 11111111 has its top bit set, marking it negative. Changing the width doesn't change the bits; it changes how the top bit is read.

Bitwise operations that wrap like hardware

Choose an operation — AND, OR, XOR, NOT, shift-left (SHL), or shift-right (SHR) — and, for everything except NOT, a second operand B. NOT is unary, so its operand field disappears. The result is shown three ways: hex, decimal, and binary grouped into readable chunks.

Everything is masked to the selected width, which is the whole point. NOT 0 at 8-bit is 255 (0xFF), but at 32-bit it's 4294967295 (0xFFFFFFFF) — the same operation, a different register size. 1 SHL 4 gives 16; shift far enough left and the high bits fall off the end of the register instead of growing the number, exactly like << on a fixed-size integer in C, Rust, or Go. This makes the tool useful for reasoning about flag masks, packing fields into a word, or checking why a shift overflowed in your code.

A common gotcha

Operand B is parsed in the same base as your main input. If you're in hex mode and want to AND with decimal 12, either switch to decimal first or type 0xC. Likewise, shift amounts are read in the current base — an easy thing to trip over when you leave the tool set to hex.

Privacy

Every conversion and bitwise operation is plain local arithmetic on numbers you type. Nothing is sent to a server, so you can safely paste values from private systems.