Decimal Converter

About Decimal converter

Converts whole numbers between decimal and binary, octal or hexadecimal. The Decimal to Other tab starts from a base-10 value, and the Other to Decimal tab reads a number written in the base you choose. It converts numbers rather than text, so it is aimed at students and programmers moving between number systems.

How to use it

1. On Decimal to Other, type a value into the Decimal Number field.
2. Pick Binary, Octal or Hexadecimal in the Convert To menu and press Convert.
3. For the other direction, open Other to Decimal and choose the source in the Convert From menu.
4. Enter the digits, press Convert to Decimal and use the copy icon beside the result.

255 in three bases

255

Binary 11111111, octal 377, hexadecimal FF

When to use it

• Checking homework on positional number systems before handing it in.
• Converting a color channel value such as 200 to hex for a stylesheet.
• Reading a register or flag value given in hexadecimal as an ordinary number.
• Working out how many bits a value needs by looking at its binary length.

Questions about Decimal converter

What happens to a decimal fraction like 12.7?

It is refused with a message saying the decimal point is not a digit, rather than being silently cut to 12. The tool has no way to convert fractional binary or hex digits.

Can it handle negative numbers?

Yes, in both directions. -10 becomes -1010 in binary, with a minus sign in front rather than a two's complement pattern, and -1010 read as binary gives -10 back.

How large can the numbers be?

There is no practical limit. The math is exact, so 9007199254740993, one past the largest safe integer in ordinary double-precision arithmetic, converts to hexadecimal 20000000000001 without rounding.

May I type a prefix such as 0x or 0b?

Yes, when it matches the base you chose in Convert From, so 0xFF works with Hexadecimal and 0b101 works with Binary. Spaces or underscores between digits are ignored, and hex letters can be upper or lower case.

Is hexadecimal output upper or lower case?

Upper case, so 255 becomes FF. Binary and octal contain only digits and are unaffected.

Related tools

• Octal converterConvert whole numbers between octal and decimal, binary or hexadecimal.
• Binary converterConvert text to binary and the other way for any string input.
• Hex converterConvert text to hexadecimal and the other way for any string input.
• Number to words converterConvert a number to written, spelled out words.
• Number base converterConvert an integer between any bases from 2 to 36 at once.
• Color converterConvert your color to multiple other formats.