MSI-1010 Generator
MSI with two modulus-10 checks for high-value inventory items.
How MSI-1010 is structured
MSI-1010 is base MSI carrying two mod-10 check digits. The bar pattern is the MSI pattern throughout — numeric data, four bits per digit, each bit drawn as a 100 or 110 group — so the only structural consequence of the second check digit is two extra characters at the end of an already long symbol.
MSI-1010 check digit
The first check digit is the Luhn-style mod-10 sum over the data digits. The second is computed the same way over the data plus the first check digit, so it guards against a corrupted first check digit as well as against data errors. Both must validate; a reader that expects a single check digit will return the second one as data.
MSI-1010 compared with MSI-10
MSI-10 is the same calculation applied once and is the right choice when label width is tight. MSI-1110 replaces the second mod-10 with a mod-11 first digit, gaining transposition detection; MSI-1010 simply doubles down on the mod-10 arithmetic that an existing inventory scheme already implements. Compare the MSI-10 generator page for the same breakdown of structure, check digit and use cases.
Common MSI-1010 problems
The reader validates only one check digit
A profile configured for MSI-10 treats the second check digit as payload, so every scan comes back one digit longer than expected. Change the reader profile to MSI-1010, or generate MSI-10 if the application only requires one.
The second check digit was computed over the data only
It has to be computed over the data plus the first check digit. Recomputing both from the raw data gives a valid-looking symbol that fails validation on every reader set up for the variant.
The label runs out of width
Two extra characters on a symbology that is already wide is often what pushes MSI past the printable panel. Count the digits before committing to the variant — MSI-10 or Code 128 C may be the pragmatic answer.
Where MSI-1010 is used
- High-value inventory items where two checks are mandated
- Schemes migrating from a single mod-10 without changing the arithmetic
- Internal tracking numbers with strict re-entry validation
Not sure this is the right symbology? The barcode format guide groups every supported 1D and 2D format by industry with its character set and limits.