Calculating UPC Barcode Check Digits

[ktothek]

Hello everyone,

I am new at the forum, and have a tricky question.

My company uses UPC codes for identifying its products. As you might know, the UPC codes have 11 digits + 1 digit check code. And the formulation to calculate this check digit is as following:

Step One: From the right to the left, start with odd position, assign the odd/even position to each digit.

Step Two: Sum all digits in odd position and multiply the result by 3. (7+6+1+1+5+2)*3=66
Step Three: Sum all digits in even position. (2+4+2+7+4)=19
Step Four: Sum the results of step three and four: 66+19=85
Step Five: Divide the result of step four by 10. The check digit is the number which adds the remainder to 10. In our case, divide 85 by 10 we get the remainder 5. The check digit then is the result of 10-5=5.



So, what I did to calculate this was like that:
1. Cell A1 is the eleven digit number: 72641217542
2. Cells A2 to A12 are 7, 2, 6, 4, 1, 2, 1, 7 ,5, 4, 2 correspondingly.
3. Cell A13 has the following formula to calculate the check digit:

=RIGHT(ROUNDDOWN((10-((((((A12+A10+A8+A6+A4+A2)*3)+(A3+A5+A7+A9+A11))/10)-ROUNDDOWN((((A12+A10+A8+A6+A4+A2)*3)+(A3+A5+A7+A9+A11))/10,0))*10)),0),1)


4. Cell A14 has the following formula to combine whole:

=CONCATENATE(A1,A13)


I know it is complicated but it works perfectly. Could you guys advice me any other shorter ways to do that?

Thanks in advance,

Ray

 

[custardcrumble]

Welcometo the board!

There must be a better way of getting the Odds/Evens but this is a little shorter:

=CONCATENATE(A2,10-MOD(((B2+D2+F2+H2+J2+L2)*3)+(C2+E2+G2+I2+K2),10))

A2 is the 11 digit number and B2:L2 are the individual digits
HTH
CC

 

[ktothek]

Thanks for your answer.

I gave that a try but it calculates some of them but gives wrong numbers for somes. Check that number both manually and with your formula:

84479400005

It should be 6 but your formula calculates 7.

Maybe a slight correction in the formula could correct it.

Thanks again.

Ray

 

[stapuff]

Put the UPC # in A1

Put the following in B1 =CONCATENATE(A1,RIGHT(ROUNDDOWN((SUM(RIGHT(A1,1)+MID(A1,9,1)+MID(A1,7,1)+MID(A1,5,1)+MID(A1,3,1)+LEFT(A1,1))*3+SUM(MID(A1,10,1)+MID(A1,8,1)+MID(A1,6,1)+MID(A1,4,1)+MID(A1,2,1))),1)))

Kurt

 

[Andrew Fergus]

I independently came up with the same formula as custardcrumble, being:
=10-MOD(((A12+A10+A8+A6+A4+A2)*3)+(A3+A5+A7+A9+A11),10)

Manually check your maths on 84479400005 - I believe the answer should be 7 per your instructions in your first post.

Andrew

 

[custardcrumble]

Hmm, I've done it manualy and get 7...
Odds: 8+4+9+0+0+5=26, times 3=78
Evens: 4+7+4+0+0=15
Sum=93
Remainder = 3
10-Remainder=7...

Or have I misinterpreted your description?
CC

 

[Andrew Fergus]

Hi Kurt

I think you left out the 10- part.

Andrew

 

[custardcrumble]

Agree with stapuff about using MID to save writing out the digits separately or you could write a simple macro to do it for you. Depends how easy to read you want your formula!

CC

 

[stapuff]

the rounddown right 1 of the result automatically gives you the remainder, doesn't it?

 

[custardcrumble]

But the checksum is stipulated as 10-remainder...