🔢 Number Base Converter
Enter a whole number and the base it is written in. You get it in all four common bases.
Converted number
How the Number Base Converter works
The number is read in its base to get its value, then written out again in each base. Very large numbers are handled exactly.
Decimal 255 = 1111 1111 (binary) = 377 (octal) = FF (hex)
Each binary digit is a power of 2; each hex digit is 4 binary digits.
Step-by-step calculation
- 1Enter the number.
- 2Choose its base.
- 3Read the value in binary, octal, decimal and hex.
Worked example
255 in decimal is 11111111 in binary, 377 in octal and FF in hexadecimal.
Why use a Number Base Converter?
Convert numbers for programming, networking and electronics.
Important factors that can affect your results
- Valid digits for each base.
- Negative number storage in computers.
- Very large values.
Frequently asked questions
What digits does hexadecimal use?
0–9 and A–F, where A = 10 and F = 15.
Can I convert negative numbers?
Yes, a minus sign is kept. Computers often store negatives differently (two's complement).
Related calculators
Last reviewed November 2026 · How we build and check our tools · Report a problem