A valid number may be made up
About 1 in 10 random numbers has a correct check digit. Google says to submit a GTIN only when you are sure it is correct, and to leave it out when in doubt.
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GTIN check digit calculator
Calculate the check digit from the first 7, 11, 12 or 13 digits of a GTIN, or validate a full GTIN-8, UPC (GTIN-12), EAN (GTIN-13) or GTIN-14 before it goes into your product feed. Every step of the mod-10 sum is shown.
Berend Vrakking, founder. Last updated .
Your result
The check digit for 871234567890 is 6. The full GTIN is 8712345678906, a GTIN-13 (EAN-13).
- Check digit
- 6
- Format
- GTIN-13
- Full GTIN
- 8712345678906
The sum, digit by digit
| Position from the right | Digit | Weight | Product |
|---|---|---|---|
| 1 | 0 | × 3 | 0 |
| 2 | 9 | × 1 | 9 |
| 3 | 8 | × 3 | 24 |
| 4 | 7 | × 1 | 7 |
| 5 | 6 | × 3 | 18 |
| 6 | 5 | × 1 | 5 |
| 7 | 4 | × 3 | 12 |
| 8 | 3 | × 1 | 3 |
| 9 | 2 | × 3 | 6 |
| 10 | 1 | × 1 | 1 |
| 11 | 7 | × 3 | 21 |
| 12 | 8 | × 1 | 8 |
| Sum | 114 | ||
| Next multiple of ten | 120 | ||
| Check digit | 6 | ||
The start values are illustrative data.
How it works
Every step of the check digit, worked through for the start value.
Illustrative data. The first 12 digits of a GTIN-13 are 871234567890. Number them from the right, weight them 3, 1, 3, 1 and so on, and add the products.
| Step | Calculation | Result |
|---|---|---|
| Digit 1: 0 | 0 × 3 | 0 |
| Digit 2: 9 | 9 × 1 | 9 |
| Digit 3: 8 | 8 × 3 | 24 |
| Digit 4: 7 | 7 × 1 | 7 |
| Digit 5: 6 | 6 × 3 | 18 |
| Digit 6: 5 | 5 × 1 | 5 |
| Digit 7: 4 | 4 × 3 | 12 |
| Digit 8: 3 | 3 × 1 | 3 |
| Digit 9: 2 | 2 × 3 | 6 |
| Digit 10: 1 | 1 × 1 | 1 |
| Digit 11: 7 | 7 × 3 | 21 |
| Digit 12: 8 | 8 × 1 | 8 |
| Sum | 0 + 9 + 24 + 7 + 18 + 5 + 12 + 3 + 6 + 1 + 21 + 8 | 114 |
| Next multiple of ten | 114 rounded up | 120 |
| Check digit | 120 − 114 | 6 |
The check digit is 6, so the full GTIN is 8712345678906. To validate a GTIN, run the same sum on every digit except the last and compare the result with the last digit. Weighting the check digit too, with weight 1, brings the total to 120, a multiple of ten.
Formats
The same sum covers every format, only the length changes.
Merchant Center treats UPC, EAN, JAN, ISBN-13 and ITF-14 codes as GTINs. The calculator tells them apart by length, and by the 978 or 979 start of an ISBN-13.
| Digits | Format | Barcode names |
|---|---|---|
| 8 | GTIN-8 | EAN-8, JAN |
| 12 | GTIN-12 | UPC (North America) |
| 13 | GTIN-13 | EAN (Europe), JAN, ISBN-13 for books |
| 14 | GTIN-14 | ITF-14, for multipacks |
Google asks for 12-digit codes instead of 8-digit UPC-E codes, and for ISBN-13 instead of ISBN-10. This calculator does not convert either: it reads 8 digits as a GTIN-8.
Limits
A valid check digit only catches typing mistakes, and Merchant Center asks for more.
Restricted and coupon ranges
Google says not to submit numbers that start with 02, 04 or 2 (restricted) or 05, 98 or 99 (coupon). The calculator flags them for 8, 12 and 13 digit codes.
Every variant has its own GTIN
A different colour or size has its own GTIN, so check each variant row, not the product once.
Leading zeros disappear in spreadsheets
A UPC that starts with 0 loses it when a spreadsheet stores the number as a number. Add the zero back before you validate, and keep the column as text.
GTIN check digit questions, answered.
How do you calculate a GTIN check digit?
Number the digits without the check digit from the right and weight them 3, 1, 3, 1 and so on. Add the products and subtract the sum from the next multiple of ten. For 871234567890 the sum is 114, the next multiple of ten is 120, so the check digit is 6 and the GTIN is 8712345678906. The method is the same for GTIN-8, 12, 13 and 14.
How do you check whether a GTIN is valid?
Take every digit except the last, calculate the check digit as above, and compare it with the last digit. If they differ, the number has a typing mistake or is not a real GTIN. Switch the calculator to "Validate a GTIN" to see the comparison. Merchant Center asks for a check digit that is present and correct.
Does a valid check digit mean the GTIN belongs to my product?
No. The check digit only shows that the digits are consistent with each other. Google says to provide a GTIN only if you are sure it is correct, and the right number is the one the manufacturer assigned to that product and variant. Take it from the packaging, the manufacturer or your supplier.
Is the check digit the same for UPC, EAN and ISBN-13?
Yes for UPC (12 digits), EAN (13), ITF-14 (14) and ISBN-13: all use the same 3 and 1 weights. An ISBN-10 uses a different method, so convert it to ISBN-13 first, which is what Google asks for anyway.
What does Merchant Center do with a wrong GTIN?
Google says products with a missing or incorrect GTIN may have limited visibility, and that matching to a product cannot be assured without one. It lists a present and correct check digit, no restricted or coupon ranges and no GTIN for products that have none (for example your own store brand) as requirements.
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