Beyond base 36
Bases 2–36 accept letters case-insensitively. Bases 37–62 use 0–9 A–Z a–z and therefore become case-sensitive.
Exact rational—
Source base—
Bit length—
Target guard—
Processing0 ms
Conversion audit
Exactness first
All arithmetic uses BigInt numerator/denominator pairs. No IEEE-754 floating-point number is used to represent the value, so 64-bit IDs, hashes and long fractions are not silently rounded.
Ready. Parentheses mean a repeating fractional cycle, e.g. 0.(3).
Conversion steps
Signed two’s-complement lab
Signed value—Unsigned interpretation—Hex pattern—Binary pattern—
Available for integers that fit the selected signed width.
Batch base conversion
Enter one number per line. All valid rows are converted using the current source and custom target bases. Invalid rows stay visible with line-specific diagnostics.
| Line | Input | Exact rational | Output | Status |
|---|
Exact repeating fractions
Use parentheses for repeating digits: 0.(3) in base 10 is exactly one third. Outputs use the same notation when the cycle is detected.
Huge integers stay exact
The converter does not pass values through JavaScript Number. Arbitrarily large integer values are accumulated and emitted with BigInt arithmetic.
Prefixes and separators
Auto mode recognizes 0b, 0o and 0x. Spaces and underscores are accepted as visual digit separators and do not change the value.
Two’s complement
The integer lab shows the exact bit pattern for signed 8/16/32/64/128/256-bit values and blocks values that do not fit instead of wrapping silently.
Very long periods
Some rational values have extremely long repeating expansions. You can raise the digit limit; when the limit is reached before the period closes, the result is explicitly marked truncated while the exact rational remains available.