Check Digit Calculator
What is a Check Digit and a Check Digit Calculator?
The last digit of all numeric fixed-length GS1 Identification (ID) Keys is a check digit, which is required and ensures the integrity of the key. The last digit, being the check digit, is calculated using a simple algorithm based on the preceding numbers in the key. The result is an accurately constructed and scannable barcode.
This page provides information for each GS1 ID Key, shows how the calculator works and even provides you step by step instructions on how to manually calculate the check digit by using the simple algorithm, should the need arise.
- Global Trade Item Number (GTIN) Check Digit Calculator
The four different formats of GTIN include GTIN-8, GTIN-12, GTIN-13 and GTIN14.
- Serial Shipping Container Code (SSCC) Check Digit Calculator
Enter 17 digits to calculate the 18th digit, which is the check digit.
- Global Location Number (GLN) Check Digit Calculator
Enter 12 digits to calculate the 13th digit, which is the check digit.
- How does the check digit calculator work?
The check digit is calculated using a simple algorithm, based on the numbers preceding the check digit of the key.
- How to manually calculate the check digit?
A step by step algorithm with examples of 1 number without the check digit, the calculations and end result the number with the check digit.
Step 1: Multiply, Step 2: Add, and Step 3 Subtract.
How does the check digit calculator work?
|
ID Key Format |
Digit Positions |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
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 |
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|
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 |
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Step 3: Subtract sum from the next highest multiple of ten = Check digit |
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How to manually calculate the check digit?
|
Positions |
N1 |
N2 |
N3 |
N4 |
N5 |
N6 |
N7 |
N8 |
N9 |
N10 |
N11 |
N12 |
N13 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Number without check digit |
|
|
|
|
|
|
|
|
|
|
|
|
- |
|
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 sum from next highest multiple of ten = 60 - 57 = 3 (check digit) |
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|
Number with check digit |
6 |
2 |
9 |
1 |
0 |
4 |
1 |
5 |
0 |
0 |
2 |
1 |
3 |