Binary to Decimal & Hex Converter

Example: a 64-bit ID That JavaScript Cannot Hold

Discord IDs are 64-bit “snowflakes”, and the Discord API reference says they are sent as strings “to prevent integer overflows in some languages”. The documentation’s sample ID is 175928847299117063. With Decimal selected and Two’s complement set to 64-bit:

• Hex: 271065AC1020007
• 64-bit binary: 0000001001110001000001100101101011000001000000100000000000000111

The first 42 bits hold the time. Paste them back with Binary selected:

The result is 41944705796 milliseconds after the Discord epoch, the same number as in the documentation’s diagram. The ID itself is larger than Number.MAX_SAFE_INTEGER (2^53 − 1, MDN), so parseInt('175928847299117063') returns 175928847299117060. This tool parses every digit with BigInt and keeps all 18.

Example: Negative Numbers and Two’s Complement

Different tools write −10 in binary in different ways. JavaScript’s (-10).toString(2) gives -1010: a minus sign in front of the magnitude. Java’s Integer.toBinaryString(-10) gives the 32-bit pattern, because Java stores an int in two’s complement. This tool shows both:

• Binary row: -1010
• 8-bit row: 11110110 (hex F6), with the note “unsigned 246, signed −10”
• 32-bit hex row: FFFFFFF6

To read a pattern from a register dump or a hex editor, type it, pick the width and tick Read input as signed. FFFFFFF6 with 32 bits reads as −10. A value outside the width, such as −129 for 8 bits, is reported with the range −128 to 255 (the signed and unsigned ranges together).

Example: Fractions That Never End

0.1 in decimal becomes 0.0(0011) in binary and 0.1(9) in hex. The digits in parentheses repeat forever. That is why a JavaScript Number, which is an IEEE 754 double (MDN), cannot hold 0.1 exactly and 0.1 + 0.2 is not 0.3. Fractions whose denominator divides a power of the new base do end: 0.625 is 0.101 in binary and 0.A in hex.

The tool does the arithmetic on exact fractions, so it never rounds. If the repeating block is longer than 64 digits, it shows the first 64 digits and an ellipsis.

What You Can Paste

Anything else stops the conversion and names the character and its position, for example "2" at position 5 is not a base-2 digit (allowed: 0–1) for 10102. JavaScript’s parseInt('10102', 2) returns 10 instead: it stops at the first bad digit without an error.

How This Differs From RapidTables

RapidTables is the first Bing result for “binary to decimal”. We gave both tools the same inputs on 2026-10-01. RapidTables handles large integers correctly (9007199254740993 → hex 20000000000001). These cases differ:

• Decimal 0.1 → RapidTables gives 0.0001100110011001101 and 0.1999999999999999999A, cut and rounded without a mark. This tool gives 0.0(0011) and 0.1(9).
• Decimal -10 → RapidTables picks a 16-bit two’s complement on its own. Here you choose the width.
• 1111_0000, ２５５ and 1,000 → RapidTables shows “Illegal input!” without saying which character. This tool converts them.

Limits

• Bases 2 to 36 with the digits 0–9 and A–Z, the same range as Python’s int() and JavaScript’s toString(). Base 58, base 62 and Base64 alphabets are not supported.
• Up to 20,000 digits. Python’s int() stops at 4,300 decimal digits by default (Python docs), so a very long result from here may need sys.set_int_max_str_digits() there.
• The parentheses in 0.0(0011) are notation for reading. No input box, including this one, accepts them back.
• The tool converts exact numbers. It does not show the IEEE 754 bit layout of a float (sign, exponent, mantissa).
• Two’s complement needs an integer and one of the five widths. Excel-style 10-bit or 40-bit patterns appear as the low bits of the 16-bit or 64-bit row.

For text instead of numbers, use the Text to Binary Translator or the ASCII Converter. Octal file modes have their own Chmod Calculator, and subnet masks in binary are in the IP Subnet Calculator.