Binary Converter
Convert signed integers and fractions between bases 2-36 without losing large-number precision. Repeating and truncated fractions are labelled.
Up to 512 digits. Integers use exact arbitrary-precision math. Fractional outputs show exact, repeating, or truncated status.
This panel deliberately uses browser IEEE 754 Number/Float32 rounding. It is separate from the exact base converter.
How to convert numbers between bases
A number base (or radix) determines the available digits and each digit's positional value. Decimal uses 0-9, binary uses 0-1, and hexadecimal uses 0-9 plus A-F. This converter supports signed values in bases 2-36. Integer conversion uses arbitrary-precision math, so values larger than JavaScript's safe-integer limit are not rounded.
- Pick the base of the number you already have from the Input dropdown (decimal, binary, hex, octal, or Custom for bases 2-36).
- Type up to 512 digits, with an optional sign and one radix point. Do not add programming prefixes such as
0bor grouping separators. - Read each result's precision label. Exact values terminate; repeating cycles appear in parentheses; an ellipsis means the display stopped after 32 fractional digits.
- Use the method panel to see the exact decimal integer or reduced rational value behind the display.
To convert by hand, multiply each digit by its base raised to the digit's position and sum them for the decimal value (for example binary 1011 = 1×2³ + 0×2² + 1×2¹ + 1×2⁰ = 11). To go from decimal to another base, divide repeatedly by the target base and read the remainders from bottom to top. Because each hex digit maps to exactly 4 binary bits and each octal digit to 3 bits, hex and octal are compact shorthands for binary.
The supporting panels have narrower contracts: IEEE 754 deliberately shows rounded browser Float32 and Float64 layouts; two's complement checks signed 8/16/32/64-bit ranges; bitwise operations use signed 32-bit semantics; and binary arithmetic accepts signed integers with exact large-number results. All calculations run locally in this browser tab and are not saved automatically.