EAN-13 & UPC-A Check Digit Calculator
Calculate the exact 13th digit for EAN-13, 12th digit for UPC-A, 8th digit for EAN-8, or 14th digit for ITF-14 using the official Modulo-10 weighted sum algorithm.
Mathematical Breakdown (Modulo-10 Weighted Sum):
| Position | #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | #11 | #12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Digit | 4 | 0 | 0 | 6 | 3 | 8 | 1 | 3 | 3 | 3 | 9 | 3 |
| Weight | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 | ×1 | ×3 |
| Product | 4 | 0 | 0 | 18 | 3 | 24 | 1 | 9 | 3 | 9 | 9 | 9 |
Total weighted sum = 89. The nearest multiple of 10 is 90. Check digit = 90 − 89 = 1.
How the Modulo-10 Check Digit Works
The Modulo-10 algorithm is the global standard defined for EAN-13, UPC-A, EAN-8, and ITF-14 symbols. It ensures that single-digit substitution errors and transposition errors (swapped adjacent digits) are caught instantly at checkout scanners before an incorrect product price is rung up.
By multiplying alternating digits by 3 and 1 starting from the rightmost payload digit, any single-digit error changes the final sum by an amount that cannot divide evenly by 10, preventing scanner errors.
A 12-digit UPC-A (e.g. 036000291452) is functionally equivalent to an EAN-13 with a leading zero (0036000291452). Both use the exact same check digit formula.