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UPC Modulo checksum formula

For those of you who wish to calculate your own mod check character, here is the formula.
To follow, use this UPC as an example: 0-12345-67890-?

Step 1 Starting at the left, sum all the characters in the ODD positiions (e.g. first from the left, third from the left, etc.) STARTING WITH THE NUMBER SYSTEM CHARACTER
.0 + 2 + 4 + 6 + 8 + 0 = 20

Step 2 Multiply the sum we got in Step 1 by 3.
20 x 3 = 60

Step 3 Starting at the left, sum all the characters in the EVEN positions.
1 + 3 + 5 + 7 + 9 = 25

Step 4 Add the product of Step 2 to the sum of Step 3.
60 + 25 = 85

Step 5 The modulo-10 check digit value is the smallest number which produces a multiple of 10, when added to the sum in Step 4.
Hence, our check digit is 5.

Our completed UPC would then be 0-12345-67890-5.

Data Index ModCheck Software Availability:

Our Windows version of Data Index ModCheck is available. It sells for $25, plus shipping and handling. Or you may download the software for $9.95.

	For those of you who wish to calculate your own mod check character, here is the formula. To follow, use this UPC as an example: 0-12345-67890-?
Step 1	Starting at the left, sum all the characters in the ODD positiions (e.g. first from the left, third from the left, etc.) STARTING WITH THE NUMBER SYSTEM CHARACTER .0 + 2 + 4 + 6 + 8 + 0 = 20
Step 2	Multiply the sum we got in Step 1 by 3. 20 x 3 = 60
Step 3	Starting at the left, sum all the characters in the EVEN positions. 1 + 3 + 5 + 7 + 9 = 25
Step 4	Add the product of Step 2 to the sum of Step 3. 60 + 25 = 85
Step 5	The modulo-10 check digit value is the smallest number which produces a multiple of 10, when added to the sum in Step 4. Hence, our check digit is 5.

	Our completed UPC would then be 0-12345-67890-5.

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Check back later for software downloads and other works in progress.

Data Index ModCheck Software Availability: