Hex to Decimal Converter

Type or paste a hexadecimal number into Hexadecimal input and Decimal result fills in as you type. The answer is exact however long the number is, with no 64-bit or 2^53 limit. Prefixes like 0x and #, spaces, commas and underscores are ignored, so a raw dump such as 0xDE, 0xAD, 0xBE, 0xEF can be pasted as it is. The conversion runs in your browser and nothing is uploaded or saved.

How to convert hex to decimal

1. Type or paste your hex number into Hexadecimal input, for example 0xFF or DE AD BE EF.
2. Read Decimal result. It updates on every keystroke, so there is no convert button to press.
3. Select Copy decimal to put the number on your clipboard. The button reads Copied for a moment to confirm.
4. For a long number, turn on Group digits with separators to split the result into groups of three digits, using the separator of the page language (1,208,925,819,614,629,174,706,175 in English, with dots in German). It is off by default, so the copied number is plain digits unless you switch it on.
5. Select Clear, which appears once there is input, to start over.

What you can paste into the hex box

Whitespace, commas, semicolons and underscores are treated as separators and dropped. Each chunk may start with 0x or #. Upper and lower case are both fine, and so are leading zeros.

Any other character, such as a G, a minus sign, a dot or a trailing h, shows the notice "G" is not a hex digit. Hex uses 0-9 and A-F. with the character it found, and Decimal result stays empty until you remove it.

Hex to decimal examples

How to convert hex to decimal by hand

Hex is base 16. Each digit is worth 16 times the digit to its right: the places from the right are 1, 16, 256, 4096 and so on. Multiply each digit by its place and add them up. The letters stand for the numbers after 9.

Worked example for 1A3F: 1 x 4096 + 10 x 256 + 3 x 16 + 15 x 1 = 4096 + 2560 + 48 + 15 = 6719. Type 1A3F into Hexadecimal input to check it. By hand this gets slow past a handful of digits, which is where a converter earns its place.

Large hex numbers: 64-bit, 128-bit and longer

Converters built on ordinary floating-point numbers can only hold whole values exactly up to 9007199254740991 (2^53 - 1), and beyond that the last digits are rounded. This page uses JavaScript BigInt instead, so a 64-bit hash fragment, a 128-bit identifier or a 256-bit key converts to its exact decimal value, digit for digit. The limit is 50,000 hex digits. Above that a notice tells you how many digits you entered and asks you to shorten the input.

What this converter does not do

• It reads every value as unsigned. There is no negative number, two's complement or signed reading, so FFFFFFFF is 4294967295, not -1.
• It converts whole numbers only. Hex with a point, like 1.8, is rejected.
• It converts hex to decimal one way. For decimal to binary, the Number mode of the Binary Translator does that.
• A colour code such as #FF8800 is read as one number, not split into red, green and blue.
• The bytes are read in the order you write them and are never swapped.
• If your hex is the bytes of encoded text rather than a number, the Base64 Converter handles Base64 to and from text.

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