Check Digit Calculator

Written by Anon.

The last digit of a bar code number is a computer Check Digit which makes sure the bar code is correctly composed.

This page contains the following information:

How to calculate a Check Digit manually

ID Key Format	Digit positions
GTIN-8											N₁	N₂	N₃	N₄	N₅	N₆	N₇	N₈
GTIN-12							N₁	N₂	N₃	N₄	N₅	N₆	N₇	N₈	N₉	N₁₀	N₁₁	N₁₂
GTIN-13						N₁	N₂	N₃	N₄	N₅	N₆	N₇	N₈	N₉	N₁₀	N₁₁	N₁₂	N₁₃
GTIN-14					N₁	N₂	N₃	N₄	N₅	N₆	N₇	N₈	N₉	N₁₀	N₁₁	N₁₂	N₁₃	N₁₄
SSCC	N₁	N₂	N₃	N₄	N₅	N₆	N₇	N₈	N₉	N₁₀	N₁₁	N₁₂	N₁₃	N₁₄	N₁₅	N₁₆	N₁₇	N₁₈
Step 1: Multiply value of each position by
	x3	x1	x3	x1	x3	x1	x3	x1	x3	x1	x3	x1	x3	x1	x3	x1	x3
Step 2: Add results together to create sum
Step 3: Subtract the sum from nearest equal or higher multiple of ten = *Check Digit*

The following table gives an example to illustrate how a Check Digit is calculated:

Positions	N₁	N₂	N₃	N₄	N₅	N₆	N₇	N₈	N₉	N₁₀	N₁₁	N₁₂	N₁₃
Number *without* Check Digit	6	2	9	1	0	4	1	5	0	0	2	1	-
Step 1: Multiply	x	x	x	x	x	x	x	x	x	x	x	x	-
by	1	3	1	3	1	3	1	3	1	3	1	3	-
Step 2: Add results	=	=	=	=	=	=	=	=	=	=	=	=	-
to create *sum*	6	6	9	3	0	12	1	15	0	0	2	3	= 57
Step 3: Subtract the sum from nearest equal or higher multiple of ten = 60- 57 = 3 (Check Digit)
Number *with* Check Digit	6	2	9	1	0	4	1	5	0	0	2	1	3

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Last Updated (Wednesday, 02 September 2009 22:05)