GS1 Modulus 10 Calculator

How GS1 Modulus 10 Calculator Works?

The GS1 Modulus 10 Calculator works by multiplying payload digits by alternating weights of 3 and 1 starting from the rightmost digit, summing the products, and subtracting the last digit of the sum from 10. GS1 is the global standards body behind barcodes such as EAN-13 and UPC-A.

1. 1Strip spaces and keep only the digits of the payload.
2. 2Give the rightmost payload digit a weight of 3, the next digit a weight of 1, and keep alternating to the left.
3. 3Multiply each digit by its weight.
4. 4Add all products to get the weighted sum S.
5. 5Compute the check digit as (10 − (S mod 10)) mod 10.

GS1 Modulus 10 Calculator Formula

The GS1 Modulus 10 formula is Check Digit = (10 − (Σ dᵢ·wᵢ mod 10)) mod 10, with wᵢ = 3 for odd positions and wᵢ = 1 for even positions counted from the right.

S = Σ dᵢ × wᵢ,  wᵢ = 3 if i odd, 1 if i even (i counted from the right, starting at 1)
Check Digit = (10 − (S mod 10)) mod 10   (GS1 MODULUS 10)

• dᵢ is the payload digit at position i from the right.
• wᵢ is the weight 3 or 1.
• S is the sum of all digit × weight products.

0 × 3 = 0
9 × 1 = 9
8 × 3 = 24
7 × 1 = 7
6 × 3 = 18
5 × 1 = 5
4 × 3 = 12
3 × 1 = 3
2 × 3 = 6
1 × 1 = 1
S = 85
Check digit = (10 − (85 mod 10)) mod 10 = 5

GS1 Modulus 10 Calculator Conversion Table

The GS1 Modulus 10 conversion table maps remainders of S mod 10 to check digits and shows real GS1 key lengths.

The first two columns are the remainder lookup. The sample columns show real GS1 key types computed with the same rule; their remainders vary.

What is GS1 Modulus 10 Calculator?

A GS1 Modulus 10 Calculator is a tool that computes the standard check digit used by every numeric GS1 identification key. GTIN-8, GTIN-12, GTIN-13, GTIN-14, GLN, SSCC, GSRN, and GSIN all share the same algorithm.

The GS1 Modulus 10 check digit detects 100% of single-digit errors and about 89% of adjacent transpositions. Swaps of two digits that differ by 5 (such as 16 ↔ 61) go undetected.

What are the uses of GS1 Modulus 10 Calculator?

There are 5 main uses of the GS1 Modulus 10 Calculator, including barcode creation, supplier onboarding, and label printing.

• Barcode creation: Brand owners complete GTINs before printing EAN-13 or UPC-A barcodes on packaging.
• Supplier data checks: Retail buyers reject product files with wrong check digits during supplier onboarding.
• Logistics labels: Warehouses compute the 18th SSCC digit before printing pallet labels.
• Location numbering: Companies assign Global Location Numbers (GLN) to warehouses and stores.
• System testing: Developers verify point-of-sale and Enterprise Resource Planning (ERP) checksum code against known GS1 examples.