Number Base Converter
Convert between binary, octal, decimal and hex — plus every base up to 36, with bit views and arbitrary-precision integers.
Reading numbers in other bases
A base (radix) says how many digits a number system has before it carries: binary has two, octal
eight, decimal ten and hexadecimal sixteen, where a–f stand for
10–15. Programmers meet all four constantly — bitmasks and permissions in binary, Unix file modes
in octal, colors, IPv6 and memory addresses in hex. Prefixes make the base explicit:
0b1010 (binary), 0o755 (octal), 0xFF (hex), and an
optional 0d for decimal.
Conversion here uses BigInt, so integers keep exact precision no matter how long they
are — paste a 128-bit value and every digit survives, which is exactly where JavaScript's
Number would start rounding. The bit views below the conversion table are useful when
you care about representation rather than value: bit length, bytes grouped for hex dumps, and the
two's-complement reading a 32- or 64-bit machine would see for the same bits.
FAQ
Can I convert decimals or negative numbers?
Negative integers convert directly. Fractional input in base 10 gets a floating-point view instead: its IEEE 754 double-precision bit pattern split into sign, exponent and mantissa, which is the honest answer for a value a binary machine cannot hold exactly (0.1, for example).
Why is 0.1 shown with a long mantissa?
Because 0.1 has no exact binary representation. The mantissa shows the repeating fraction that gets stored, which is why floating-point arithmetic surprises people at the last digit.
What does the two's-complement line mean?
Most languages store signed integers in two's complement: the highest bit is the sign, so the same 32 bits read as -1 when signed and 4294967295 when unsigned. The tool prints both readings whenever the value fits in 32 or 64 bits.
Is anything uploaded?
No — every conversion is plain arithmetic in your browser.