⌘ Number & Reference · Tool

Digit Sum Calculator

Add the decimal digits of an integer and optionally calculate its repeated digital root.

Enter your figures

Enter the values below to calculate your result.

Calculation Results

Based on the figures you entered.

Digit sum
39
Digital root
3
Digital root
The repeated digit sum until one decimal digit remains; for 0, the digital root is 0.

How to use this calculator

What to enter

Enter or select the following as requested: Integer. Follow the units, valid ranges, examples, and options displayed beside each field.

What the result means

The result follows the number property, divisibility rule, numeral system, or arithmetic operation named by the calculator. Check whether the input must be an integer, the selected base, sign conventions, and whether the output uses decimal, binary, hexadecimal, or another representation.

When to use it

Use this to check a number-theory problem or convert numeric representations. Verify input constraints and preserve the correct base when copying the result into another tool or calculation.