Free converter

Binary, Decimal and Hex Converter

Enter a number and its base. The converter shows the same value in binary (base 2), octal (8), decimal (10), hexadecimal (16) and base 36.

By iToolsLab Editorial TeamUpdated 14 October 2026How we build tools

What is binary, decimal and hex converter?

Computers work in binary, programmers read hexadecimal, and everyday life uses decimal. Moving between them is a daily task in programming, networking, electronics and computer science classes.

This tool converts any whole number between the common bases and checks that your digits are valid for the base you chose.

How to use the binary, decimal and hex converter

  1. Type the number.
  2. Choose the base it is written in.
  3. Read the value in all other bases.

How the binary, decimal and hex converter works

The number is first read in its own base to get a value, then written out again in each target base. Letters A to F stand for 10 to 15 in hexadecimal.

Worked example

Decimal 255 is binary 11111111, octal 377 and hexadecimal FF. Hexadecimal 1A is decimal 26.

Common uses of the binary, decimal and hex converter

  • Reading memory addresses and color codes as a developer.
  • Learning binary for computer science classes.
  • Debugging bit flags and permissions.
  • Converting between hex and decimal in networking tasks.
  • Creating short IDs using base 36.

Tips and common mistakes

Hexadecimal is popular because one hex digit equals exactly four binary digits.

Colors such as #FF8800 are three hex pairs for red, green and blue.

Background: what to know before you rely on it

Computers store data as bits, each either 0 or 1. Binary strings are long and hard to read, so programmers group four bits into one hexadecimal digit, which is why a byte is shown as two hex digits from 00 to FF. Octal groups three bits and appears in Unix file permissions, such as 755. Base 36 uses all digits and letters and is handy for short URLs. To convert by hand, repeatedly divide by the target base and read the remainders backward. Practice a few conversions and you will start to see patterns, for example that every power of two is a one followed by zeros in binary.

Private, free and fast

This tool runs entirely in your browser. What you type or choose is not uploaded to a server and is not saved after you close the page, which keeps it fast and private. It is free to use as often as you like. See more in all converters, or browse the full list of tools.

Frequently asked questions

How do I convert binary to decimal?

Multiply each binary digit by a power of 2 and add the results. Or use this tool.

What is FF in decimal?

255.

Does it support fractions?

No, whole numbers only.

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Results are for information and education. For legal, financial, medical or security decisions, check with a qualified professional. Check critical conversions with an official source.