Number Base Converter
Convert numbers between binary, octal, decimal, hex, and any base 2-36.
How to use the Number Base Converter
Step 1 — Enter a number
- Type the value you want to convert.
Step 2 — Choose bases
- Pick the base you are converting from and to.
Step 3 — Convert
- Press Convert; the result and the common bases appear.
Private
- All maths runs in your browser.
Frequently asked questions
Any base from 2 to 36, including the common ones — binary, octal, decimal, and hexadecimal — plus everything in between.
Yes. It uses arbitrary-precision integer maths, so even numbers with dozens of digits convert exactly without losing precision.
Digits 0-9 and letters a-z, used up to the value of the base. For example base 16 uses 0-9 and a-f; base 2 uses only 0 and 1. Invalid input is flagged.
Yes. Alongside your chosen conversion, it lists the value in binary, octal, decimal, and hexadecimal so you can see them together.
No. Letters in the input are treated the same in upper or lower case, and hexadecimal output is shown in uppercase by convention.
About the Number Base Converter
This tool converts a number from one base to another — between binary, octal, decimal, hexadecimal, or any base from 2 to 36. Enter a value, pick the source and target bases, and it gives you the exact result along with the common bases side by side.
Why bases matter
A number base is just how many distinct digits a system uses before it rolls over. We count in base 10, but computers work in base 2 (binary) because circuits are on or off, and programmers constantly meet base 16 (hexadecimal) because it packs four binary digits into one compact character, and base 8 (octal) in places like file permissions. Converting between them by hand is fiddly and error-prone, especially for longer values, so a reliable converter is a staple of the developer toolkit. Understanding that 255 in decimal is FF in hex and 11111111 in binary — all the same quantity, written three ways — is fundamental to working close to the machine.
Exactness with large numbers
A subtle but important detail is precision. Many quick converters route through the language native number type, which silently loses accuracy once values exceed a certain size, producing wrong digits for large inputs. This tool instead uses arbitrary-precision integer arithmetic, so a number with dozens of digits converts exactly, digit for digit, no matter the base. That makes it trustworthy for hashes, identifiers, and other large values where an approximate answer is worse than useless.
How to use it
Type your number, choose the base it is currently in and the base you want, and convert. The tool validates that every character is legal for the source base — it will tell you if you have, say, a digit 2 in a binary number — and it is not case-sensitive on input. Besides your specific conversion it always shows the value in binary, octal, decimal, and hexadecimal together, which is handy when you are reasoning across several at once. Everything runs locally in your browser.