Number Converters · Browser · Free

Hexadecimal to Decimal Converter

Enter a hexadecimal (base 16) number and read off its decimal (base 10) value. The same number is also shown in binary and octal.

Hexadecimal and decimal place values

Hexadecimal is base 16 and decimal is base 10. In a hex number the position of a digit decides what it is worth: the rightmost digit counts on its own, the digit to its left counts in sixteens, and the next one counts in units of 256, which is the value the table gives for 100. Every step further left is worth sixteen times the place before it.

The digits 0 to 9 keep their usual shape, while the letters A to F stand for the values between them. The table lists A as 10 and F as 15, so the letter F in the ones place adds fifteen.

Reading a hex number means taking each digit with its own place and adding those amounts. The table shows 1F as 31, which is one group of sixteen together with the fifteen that F carries, and it shows 64 as 100, which is six groups of sixteen plus four.

Using the converter

There is a single text field. Type one hexadecimal number, or type several separated by spaces and each one is converted on its own. A sign in front and a fractional point inside are both accepted.

Nothing is worked out until you press Convert. The answer then appears in a card below the button, giving the decimal value together with the binary and octal forms. Any letters in the answer print uppercase.

Copy writes the result and its unit to the clipboard, and Clear resets the form. All of it runs in the browser and nothing is uploaded.

Hexadecimal to decimal formula

decimal value = digit × its place + next digit × its place + and so on, where the places, counted from the rightmost digit leftwards, are 1, 16 and 256.

For 1F that is (1 × 16) + (F, which is 15), and the table confirms the answer as 31. For FF both digits carry 15, and the table gives 255.

With three digits the place worth 256 joins in. The table lists 100 as 256, and 400 as 1024.