Check DigitBarcode Ean

A decimal (or alphanumeric) digit added to a number for the purpose of detecting the sorts of errors humans typically make on data entry.

Check Equation

An equation which all the digits in a number, including the check digit, must satisfy.
We can eliminate (or easily detect) the problem of omitting or adding digits by restricting the input field to a given number of digits if we are dealing with numbers which are fixed in format, such as credit card numbers, Social Insurance Numbers, local phone numbers, and student ID numbers.

Other errors are detected by calculating whether the check equation for a particular check digit scheme is true. The check digit is included in the equation so that it is protected against errors as well. If the equation is not true, an error is present; if it is true, there may or may not be an error.


 Check Digit Calculator

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

Click on the following box to calculate the check digit direclty:

 

checkdigit 

 

How to Calculate a Check Digit Manually?

The following table  explain how to calculate the Check Digit manually for GTINs:

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