Number Base Converter

What is a Number Base Converter?

A Number Base Converter translates numbers between the four counting systems used in programming: binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16). Type a value, choose which base it is written in, and the tool shows all four representations at once — handy for color values, permission masks, memory addresses and bit-level work.

Why do large numbers stay exact?

The converter uses your browser's arbitrary-precision number type instead of floating-point math. Even values far beyond JavaScript's normal safe range convert digit-for-digit accurately and never round.

When is each base used?

• Binary (0, 1): bits, masks and bitwise operations in low-level programming.
• Octal (0–7): classic Unix file permission masks used with chmod.
• Decimal: ordinary everyday numbers.
• Hexadecimal (0–9, A–F): CSS colors such as #FF8800, memory addresses and byte values.

Is my data safe?

Yes. All conversions run in your browser; the number you type is never sent or stored. Free, no signup and no install.