Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal and any base 2–36.
About this number base converter
Computers store everything in binary (base 2), programmers often write values in hexadecimal (base 16), and humans count in decimal (base 10). This converter translates whole numbers between all of them — plus octal and base 36 — and works with numbers far larger than a calculator can hold, thanks to arbitrary-precision math.
You can paste values with common prefixes like 0x (hex) or 0b (binary); they are stripped automatically.
How to use the Number Base Converter
- Type or paste the number.
- Select the base it's written in.
- Read the value in decimal, binary, octal, hexadecimal and base 36.
How base conversion works
Each digit is multiplied by the base raised to its position, counting from zero on the right. Binary 1011 is 1×8 + 0×4 + 1×2 + 1×1 = 11. To convert decimal to another base, repeatedly divide by the base and read the remainders in reverse.
Worked example
Decimal 255 is 11111111 in binary, 377 in octal and FF in hexadecimal — the largest value that fits in one byte.
Tips for better results
- Each hex digit equals exactly four binary digits, which is why hex is a compact way to write binary.
- Web colors like #4B2BD6 are three hex bytes for red, green and blue.
Frequently asked questions
How do I convert binary to decimal?
Multiply each bit by its power of two and add them up, or paste the binary number here with input base 2.
Does this support fractions?
No — it converts whole numbers (integers), including negative numbers.
Last reviewed: October 2026 · Results are calculated in your browser.