A calculator that thinks in bits
Type an expression on the left, read four bases and a clickable bit grid on the right. Change the width, flip a cell, everything updates at once.
Input
Your expression stays in this browser. Nothing is uploaded, and there's no account. Clearing site data or switching devices will lose it. Use "Clear my data" in the footer to wipe it.
Result
Why not the built-in calculator
The stock calculator handles 1+1 just fine, but it has no idea what 0xFF & 0x0F means. Checking a mask or eyeballing one byte of binary means a window switch — more friction than the code itself.
Here the bit grid sits at the same level as the number: 8 to 64 cells, lit for 1, dark for 0. Click a cell and the value follows. Faster than shifting in your head.
How input works
0x starts hex, 0b binary, 0o octal. Bare digits follow the mode you picked on the left — in HEX mode you can just type DEAD.
Precedence, tightest first: parentheses, multiply/divide, add/subtract, shifts, AND, XOR, OR. NOT is unary — write ~ or NOT. Enter evaluates and the result drops back into the input, ready to keep going.
Width matters
In 32-bit mode, 0xFFFFFFFF + 1 is 0. Every result is truncated to the current width — overflow is not an error here, it is what the hardware does.
The DEC line shows signed and unsigned when they differ. A negative number on the grid is two's complement — the high bits all lit, easy to spot.
Common questions
Why is 255 + 1 equal to 0 in 8-bit mode?
Every result is truncated to the current width. Eight bits are already all lit at 255, so adding 1 wraps to zero. That is not a bug — it is what real hardware does. Switch to 32 or 64 bits for bigger numbers.
How do I type a hex value?
Two ways: switch the input mode to HEX and type the letters A–F directly, or use the 0x prefix in any mode, like 0x1F. Binary takes 0b and octal takes 0o, regardless of the mode.
Does my expression leave the browser?
No. The evaluator runs on BigInt inside your page. Nothing is uploaded, and the expression is only saved in this device's localStorage so it survives a refresh. Use "Clear my data" in the footer to wipe it.
Does it support decimals or floats?
No. This tool handles integers only — floats are a different binary format (IEEE 754) and mixing them in causes silent mistakes. Use a regular calculator for decimals.