Free online number base converter
Convert numbers between binary, octal, decimal, and hexadecimal instantly with this browser-based base converter. Type a value into any field and the other three update live, so you can go from binary to decimal, decimal to hex, hex to binary, or any combination without doing the math by hand. It's built for programmers debugging bit patterns, students learning number systems, and anyone who needs a quick, reliable conversion. A separate Any base panel handles unusual radixes from base 2 all the way up to base 36.
How to convert between number bases
- Pick the field that matches the base your number is already written in — Binary, Octal, Decimal, or Hexadecimal.
- Type or paste your number. Only valid digits for that base are accepted.
- Read the equivalent value instantly from the other three fields.
- For other radixes, use the Any base panel: enter the value, set the from-base and to-base (2–36), and read the result.
- Click Copy next to any value to send it to your clipboard.
Where base conversion is used
Hexadecimal shows up everywhere in computing — HTML color codes, memory addresses, and byte values are all written in hex. Binary is the raw language of hardware and bitmasks, while octal still appears in Unix file permissions. If you work with hex colors a lot, pair this with our color converter, and when you're encoding binary data for transport, the Base64 encoder is a natural next step.
Private and instant
Every conversion runs entirely in your browser using standard
parseInt and toString math — nothing is uploaded or
stored. There's no sign-up and no limit, so bookmark this page for the next
time you need to switch between bases in a hurry.