Show weights, products, and remainders.
Initialising algorithm engine for Step-by-Step Checksum Calculator...
How Step-by-Step Checksum Calculator Works?
The Step-by-Step Checksum Calculator works by printing every intermediate value of the calculation: character value, weight, product, running total, remainder, and final check character.
- 1Enter the payload and choose the scheme.
- 2List each position with its character and numeric value.
- 3Show the weight and product for each position.
- 4Show the running total after each position.
- 5Show the modulus step and the final check character.
Step-by-Step Checksum Calculator Formula
The step-by-step formula is Tₖ = Tₖ₋₁ + v(cₖ)·wₖ, then Check = g(Tₙ mod m).
T₀ = 0 Tₖ = Tₖ₋₁ + v(cₖ) × wₖ Check = g(Tₙ mod m)
Tₖis the running total after position k.gis the output rule of the scheme.
T = 83 83 mod 10 = 3 Check = (10 − 3) mod 10 = 7
Step-by-Step Checksum Calculator Conversion Table
The step-by-step table traces every position of the EAN-13 payload 590123412345.
| Position | Digit | Weight | Product | Running total |
|---|---|---|---|---|
| 1 | 5 | 1 | 5 | 5 |
| 2 | 9 | 3 | 27 | 32 |
| 3 | 0 | 1 | 0 | 32 |
| 4 | 1 | 3 | 3 | 35 |
| 5 | 2 | 1 | 2 | 37 |
| 6 | 3 | 3 | 9 | 46 |
| 7 | 4 | 1 | 4 | 50 |
| 8 | 1 | 3 | 3 | 53 |
| 9 | 2 | 1 | 2 | 55 |
| 10 | 3 | 3 | 9 | 64 |
| 11 | 4 | 1 | 4 | 68 |
| 12 | 5 | 3 | 15 | 83 |
| — | — | — | Sum mod 10 | 3 |
| — | — | — | Check digit | 7 |
What is Step-by-Step Checksum Calculator?
A Step-by-Step Checksum Calculator is a teaching and debugging tool that shows the full arithmetic behind a check digit. Each row can be compared with a program's intermediate values.
Seeing weights and products makes errors such as wrong weight direction or missing zero padding obvious.
What are the uses of Step-by-Step Checksum Calculator?
There are 3 main uses of the Step-by-Step Checksum Calculator, including code debugging, audits, and classroom teaching.
- Code debugging: Developers compare loop values with the table.
- Audits: Auditors document how a check digit was derived.
- Classroom teaching: Teachers walk students through modular arithmetic.