Numbers, Bitwise & Units
Choose the source base and compare exact integer representations.
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One signed integer, bases 2–36. Input letters ignore case. Only outer ASCII spaces, tabs and line breaks are trimmed; internal separators are rejected.
Recognized mode accepts 0b/0o/0x only when matching the source base; other bases reject these prefixes. Literal mode reads every character as a digit, including b/o/x. Output prefixes stay lowercase, after the minus sign.
Maximum 4,096 digits, counting leading zeros; at most 8,192 UTF-16 code units before trimming. No fractions, scientific notation, text bytes or two’s complement. Valid letters in higher bases remain digits.
Enter input or choose an example to begin.
A Number base converter helps compare a decimal identifier with a hexadecimal log value without rounding a long integer. The source base gives the digits their meaning; an output format only changes their representation.
Use the binary converter for bit values, hex to decimal for a debugger value, or decimal to hex for an API field. A single result set keeps the common bases beside your chosen target.
The Number base converter derives binary, octal, decimal, hexadecimal and the selected target from one integer. Changing the target does not change the mathematical value.
BigInt arithmetic retains digits beyond the safe range of ordinary JavaScript numbers. Leading zeros are normalized, so use this for values rather than fixed-width identifiers.
Start with decimal to hexadecimal, automatic conversion on, uppercase digits and no output prefix. Recognized prefixes must match the selected source base; choose literal mode when a prefix-looking sequence is part of the digits.
Automatic conversion waits 350 ms after edits. Turn it off for the Convert button or Ctrl/Cmd + Enter. Input or option changes disable copying and downloads until a new result is ready.
Swap requires a fresh result whose target digits fit the input limit. Review the complete replacement and settings, then apply. It removes the output prefix, exchanges bases and selects literal mode. Undo restores the prior input, settings and results.
Read both letter cases and choose the output letter case. Keep 2/8/10/16 results visible beside the target without converting through floating-point numbers.
Recognized mode treats leading 0b, 0o and 0x as prefix markers and checks the source base. Literal mode treats every character as a digit, resolving values such as 0x10 in base 36.
Copy or download the entire target as TXT. The JSON report contains 2/8/10/16 and the target, numerical values stored as strings, and the options snapshot used for conversion.
Swap, Example and Clear use a preview before replacement, followed by Undo. Swap preserves the value by carrying canonical signed digits into the exchanged source base.
Choose the base in which your integer is written and a target from 2 to 36. Enter the digits and compare the selected result with the common-base rows.
The maximum is 36 and the minimum is 2. Values use ten decimal digits and up to 26 Latin letters; no custom digit alphabet is accepted.
Keep a leading minus and choose base 2 as the target. Decimal -5 becomes -101. A fixed-width two’s-complement bit pattern would require a separate width choice and is not produced here.
parseInt returns a Number, so large integers can lose precision; it can also stop at an invalid character. Here the entire input is checked and the value is accumulated with BigInt.
Beyond 36, the 0–9 and A–Z alphabet would need more symbols and new case rules. This tool keeps the familiar case-insensitive alphabet.
Something looks wrong?
Try the Number base converter with a known value, confirm the source and prefix mode, then keep the full target or JSON report.