Digit sum

Client

Sum every decimal digit—handy for divisibility-by-9 checks and number puzzles.

About Digit sum

Sum the decimal digits of a whole number—local arithmetic for puzzles and divisibility checks. The interactive transform on this page runs in your browser tab—Toolcore does not need your paste for the core operation described above.

How to use this page

Paste or type in the main workspace, run the primary action from the toolbar, then copy or download the result. Use Load example when the page offers it, or URL prefill (?q= / ?qb=) so agents and tickets open the same input.

Digit sum: 15 (1 + 2 + 3 + 4 + 5)

Nearby workflows on Toolcore

  • Modulo calculator — Integer remainder and truncated quotient (a mod b)—BigInt math in your browser. when units or numeric output should be checked on a related calculator.
  • Integer base converter — Whole numbers in radices 2–36: binary, octal, decimal, hex (optional 0x), custom bases; BigInt-sized strings, local only. when units or numeric output should be checked on a related calculator.
  • Math expression evaluator — Evaluate basic + − × ÷ arithmetic with parentheses in your browser—no variables. when units or numeric output should be checked on a related calculator.
  • Luhn checksum (mod 10) — Paste a digit string (spaces ignored)—pass or fail Luhn for PANs, IMEI-style IDs, and test vectors; browser-only. when units or numeric output should be checked on a related calculator.

Common use cases

  • Verify casting-out-nines steps in arithmetic.
  • Quick checksum-style digit totals.

Common mistakes to avoid

  • Including signs or decimals

    Only non-negative whole numbers are accepted.

FAQ

Leading zeros?

They count like any other digit in the string you paste.

Is data uploaded?

No. The sum runs locally.

More tools

Related utilities you can open in another tab—mostly client-side.