MSI-11 Generator
MSI barcode with a modulus-11 check digit for shelf labels facing heavy handling.
How MSI-11 is structured
MSI-11 is the numeric-only MSI symbology with a mod-11 check digit. The bar pattern is unchanged from base MSI — each digit becomes four bits, each bit a 100 or 110 group, framed by the 110 start and 1001 stop patterns — so the practical difference from MSI-10 is entirely in how the appended digit is calculated.
MSI-11 check digit
Weights of 2, 3, 4, 5, 6 and 7 are applied to the digits from the right and repeat as needed. The weighted sum is divided by 11 and the check digit is the difference between 11 and the remainder. Because the weights are sequential, every adjacent transposition changes the sum, which is the property that the mod-10 variant lacks.
MSI-11 compared with MSI
Against MSI-10, MSI-11 trades a slightly more involved check for transposition detection, which matters where numbers are keyed by hand as well as scanned. MSI-1110 adds a further mod-10 digit after the mod-11 digit for applications that want both properties on the same symbol. Compare the MSI generator page for the same breakdown of structure, check digit and use cases.
Common MSI-11 problems
The mod-11 edge cases were computed by hand
When the weighted sum's remainder is 0 or 1 the check digit resolves to 0 or 1, and a hand-written routine that only handles the remainder case produces a digit the reader rejects. Let the generator compute it and compare against your scheme's expected value.
Weights applied from the left
The sequence 2 to 7 runs from the rightmost data digit. Reversing it changes the check digit whenever the number has an unusual length, so verify the direction in any existing check digit routine before reusing it here.
Two check digits were expected by the reader
MSI-11 appends one digit; MSI-1110 appends two. A reader profile set up for the latter returns data with a trailing digit that looks like part of the number, so align the reader and the generator on the same variant.
Where MSI-11 is used
- Shelf labels and inventory numbers that are also keyed by hand
- Warehouse locations where transposition errors are the main risk
- Legacy Plessey schemes with a mod-11 check digit
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.