GCN Check Digit Calculator

How GCN Check Digit Calculator Works?

The GCN Check Digit Calculator works by applying GS1 Modulus 10 to the 12-digit coupon payload of a Global Coupon Number (GCN) and placing the result in position 13. The optional serial component of up to 12 digits sits after the check digit.

1. 1Combine the GS1 company prefix with the coupon reference to reach 12 digits.
2. 2Multiply the 12 coupon digits by 1, 3, 1, 3… and add the products.
3. 3Subtract the last digit of the coupon sum from 10 (0 stays 0) to get digit 13.
4. 4Append an optional serial to make each coupon unique, then encode with AI (255).

GCN Check Digit Calculator Formula

The GCN formula is d₁₃ = (10 − (Σ dᵢ·wᵢ mod 10)) mod 10.

S = (d₁ + d₃ + … + d₁₁) + 3 × (d₂ + d₄ + … + d₁₂)   (GCN)
d₁₃ = (10 − (S mod 10)) mod 10   (GCN)

• d₁…d₁₂ are the 12 GCN payload digits (company prefix + coupon reference).
• d₁₃ is the GCN check digit.
• S is the weighted GCN sum.

Payload:  952123456789
Weights:  131313131313
S = 121
Check digit = (10 − (121 mod 10)) mod 10 = 9
GCN = (255) 95212345678990123456

GCN Check Digit Calculator Conversion Table

The GCN conversion table lists coupon offers with payload, check digit, and serialised GCN.

What is GCN Check Digit Calculator?

A GCN Check Digit Calculator is a tool that computes the check digit of a Global Coupon Number used for digital and paper coupons. A GCN identifies the coupon offer, and the optional serial identifies each coupon copy.

Retailers redeem GCNs at the point of sale and track which coupons were issued and used.

What are the uses of GCN Check Digit Calculator?

There are 3 main uses of the GCN Check Digit Calculator, including digital coupons, redemption control, and campaign analysis.

• Digital coupons: Retail apps issue serialised GCNs per customer.
• Redemption control: Stores block reuse of a serialised coupon.
• Campaign analysis: Marketing teams count redemptions by coupon reference.