Number base converter
Binary / octal / decimal / hexadecimal / any base from 2 to 36 · exact big numbers · fractions and bit views included
换算设置
整数用 BigInt 大数运算，不经过双精度浮点，40 位以上的十进制整数也逐位精确。
小数按分数精确换算：把你输入的小数位当分子、进制的幂当分母，约分后逐位乘目标进制，结果标注「精确」或「循环」。
位视图展示绝对值（可补到 8/16/32/64 位），不处理补码——需要补码请先确定位宽再手工换算。
换算结果
输入数值后这里会同时给出各进制结果。
FAQ
They do not. Integers run entirely through BigInt arithmetic and never pass through JS Number - double-precision floating point represents integers exactly only up to 2^53, roughly 16 decimal digits. Enter a 40-digit (or longer) decimal integer directly and the binary, hexadecimal and base-36 results are exact digit for digit.
Decimals convert exactly as fractions: your fractional digits become the numerator, a power of the base the denominator; after reducing, digits are produced by multiplying the target base step by step. If the reduced denominator contains only prime factors of the target base, the expansion terminates - labeled exact (decimal 0.5 is binary 0.1, 0.9375 is 0.1111). Otherwise it loops forever - labeled repeating (decimal 0.1 is binary 0.0001100110011… endlessly) - and then it is cut at the digit count you set, clearly marked as such.
Negatives are, keeping the conventional minus sign (decimal -255 is hexadecimal -FF). Two's complement and bitwise operations are out of scope: the bit view shows the binary grouping of the absolute value (paddable to 8/16/32/64 bits), not a two's-complement representation; if you need two's complement, fix the bit width yourself first - this tool will not guess it for you.
No upload. Parsing and conversion all run in your browser; the input never leaves the machine and reloading clears it. No need to delete prefixes by hand: input starting 0x / 0b / 0o is auto-recognized and switched to base 16 / 2 / 8 (the interface says so); spaces and underscores inside numbers are ignored as grouping (0b1010_1010 equals 10101010); hexadecimal is case-insensitive.