HesapHanem

GTIN-8 / EAN-8 Check Digit Calculator

Check or generate the check digit of an EAN-8 barcode.

How it is calculated

Only digits are read; spaces and dashes are stripped. The code must then have exactly 7 or 8 digits, otherwise there is no result. The first 7 digits are weighted alternately 3, 1, 3, 1, 3, 1, 3 from the left and added: sum = 3·d1 + d2 + 3·d3 + d4 + 3·d5 + d6 + 3·d7. The check digit is (10 − sum mod 10) mod 10, the amount that brings the sum up to the next multiple of 10. With 7 digits the tool returns the check digit and the full 8-digit code. With 8 digits it compares your last digit with the computed one and reports Valid or Invalid. A valid check digit only proves the number is well formed, not that the product is registered.

Worked example

Take the 7 digits 9638507. Multiply alternately by 3 and 1: 27, 6, 9, 8, 15, 0, 21. They add up to 86. Then 86 mod 10 = 6, and 10 − 6 = 4. The full barcode is 96385074. Entering 96385074 afterwards reports Valid, while changing the last digit to 5 reports Invalid.

Try this example →

Common mistakes

  • Applying the EAN-13 weighting (1 first, then 3). For EAN-8 the first digit is multiplied by 3.
  • Including the check digit in the sum when computing it. Only the first 7 digits are used.
  • Entering 12 or 13 digits of an EAN-13 or UPC-A code. Only 7 or 8 digits are accepted.
  • Assuming a valid check digit means the barcode is registered. It only shows that no digit was mistyped in a typical way.
  • Typing an 8-digit code with a missing or extra digit and reading the result as a failed check, when the count itself is wrong.

About this calculator

This calculator validates or completes a GTIN-8/EAN-8 barcode using its check digit algorithm: each of the first 7 digits is multiplied alternately by 3 and 1, the products are summed, and the check digit is whatever value makes that sum a multiple of 10. It's the short-format sibling of the more common 13-digit EAN, used on packaging too small for a full barcode.

Retailers, packaging designers, and developers building point-of-sale or inventory systems use it to confirm a scanned EAN-8 is valid or to generate the correct check digit for a new small-package barcode. Eight digits are validated as they stand, and seven digits produce the missing check digit.

Was this helpful?

You can pick up to 3 reactions.

Comments (1)

  • Editorial team

    The check digit catches most typing slips but not all. Swapping two neighbouring digits that differ by exactly 5, such as 3 and 8, leaves it unchanged, so 96385074 and 96835074 both pass as valid. For a code that matters, compare it digit by digit with the source rather than trusting Valid alone. Short codes are also normally assigned by your country's GS1 organisation, so a computed code is not yet yours to print. Which package needs an EAN-8?

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators