Zellio.io

Number Base Converter

Convert between binary, octal, decimal and hex — plus a bitwise calculator.

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Frequently asked questions

Which bases are supported?

Binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16), all kept in sync as you type in any one of them. These are the bases most commonly used in computing and networking, covering everything from low-level bit manipulation to human-readable decimal numbers and compact hexadecimal color codes. Type in any of the four fields and all the others update instantly, so you can work in whichever base is most natural for your task. This simultaneous conversion is faster than using a command-line calculator or converting one base at a time.

Can it do bitwise operations?

Yes — AND, OR, XOR, NOT and left/right bit shifts on two values, with the result shown across every base. Bitwise operations are fundamental to low-level programming, network masks, graphics, and cryptography, and this tool lets you visualize how they work step-by-step. Enter two numbers in any base, pick an operation, and see the binary representation with the operation highlighted and the result in all four bases. This visual approach makes understanding bitwise logic much easier than working through the math manually.

Does it handle large numbers accurately?

Yes. It uses BigInt, so large integers convert exactly without the rounding errors of normal floating-point numbers. Many calculators and programming languages lose precision with very large numbers due to floating-point representation limits. This tool uses arbitrary-precision integers (JavaScript's BigInt type), so you can convert numbers with hundreds of digits without any rounding. This is critical for cryptography, hashing, and other applications where precision over massive numbers is essential.

Pro tips

  • Read a hex value as pairs of digits when it represents bytes; the pairing is the whole reason hex is used there.
  • Use the bitwise panel to check a permission or flag value rather than reasoning about it in decimal, where the bit pattern is invisible.
  • Watch for the leading-zero octal trap when copying a permission value into source code as a number.
  • Remember that shifting left by one doubles a value and shifting right halves it, which is often a faster sanity check than converting.
  • Values beyond 2^53 stay exact here, so large identifiers and 64-bit masks convert without the silent rounding a floating-point calculator introduces.

About Number Base Converter

All four bases update together, and the bitwise side runs AND, OR, XOR, NOT and shifts across two values. BigInt underneath means numbers past 2^53 stay exact instead of quietly rounding.

Convert any integer between binary, octal, decimal and hexadecimal all at once, and run AND, OR, XOR, NOT and bit-shift operations on two values. It is an essential helper for low-level programming, embedded work, networking masks and debugging bit flags.

All four bases stay in sync as you type, so one value can be read in each without converting twice. The bitwise panel earns its place when you are working with permission bits, feature flags or network masks.

Hexadecimal dominates low-level work for one structural reason: one hex digit is exactly four bits, so a byte is always two hex digits and the mapping never needs arithmetic. That clean alignment is why colours, byte dumps, memory addresses and hashes are all written in hex rather than decimal, where no digit corresponds to a fixed number of bits.

Octal survives in one place worth knowing. Unix file permissions group nine permission bits into three digits of three bits each — read, write, execute for owner, group and others — which is why chmod 644 and chmod 755 look arbitrary until you see them as binary. A related trap: in C, Java and several other languages a leading zero marks an octal literal, so writing 0644 as an integer does not give you six hundred and forty-four.

Common use cases

  • Embedded and firmware developers reading register values and bit masks from a datasheet.
  • Network engineers converting a subnet mask or flag field between binary and decimal.
  • Developers debugging feature flags or permission bitfields where the decimal value says nothing useful.
  • Students working through computer architecture exercises and checking intermediate conversions.
  • Anyone decoding a hex colour, byte dump or memory address into something they can reason about.
How it comparesA programmer calculator such as the one in Windows or macOS covers the same ground and shows one base at a time. Seeing all four simultaneously is the difference when you are trying to spot which bit changed between two values.