Number Converters · Browser · Free

Base Converter

Type a number in the text field and use the two selects to say which base it is written in and which base to change it into. Either base can be any value from 2 to 36.

How this converter works

The form is one text field plus two selects. Enter the number using the digits of the base it is already written in, pick the base to move it to, and press Convert. The form computes only when Convert is pressed, and the answer then shows in a card below the button.

Digits run 0-9 and then A-Z, and base 36 uses Z for 35, so base 36 is the widest setting the tool offers. Press Copy to write the result and its unit to the clipboard, or Clear to reset the form and start again.

The place-value formula

A number in any base is read digit by digit from the right. The last digit is worth its own face value, the digit to its left is worth that value multiplied by the base once, the next digit multiplied by the base twice over, and so on. Adding those place values together gives the amount the number stands for, and writing that same amount with the digits of the other base is the conversion.

Letters simply act as extra digits after 9. The table below shows the digits used by some common bases, from Base 2 (binary) with 0-1 up to Base 36 with 0-9 and A-Z.