Quick guide
How to use this calculator
- Enter a signed integer.
- The sign is ignored because it is not a digit.
- Read the exact sum and digit count.
Calculation method
Add the base-ten symbols
The calculator visits every digit once and adds its integer value. It does not repeatedly reduce the answer to a digital root.
Worked example
Digit sum of 123456
Add the six written digits once.
1 + 2 + 3 + 4 + 5 + 6 = 21
Supported inputs
Precision and limits
Integer length
Use at most 2,000 digits.
Distinct from digital root
Only one sum pass is performed.