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Free MSI barcode generator.
MSI is a digits-only barcode that ends in one or two check digits. Type your number and the generator appends the mod 10 check digit.
How to create an MSI barcode
-
01
Leave the check digit out
01234567becomes012345674. A number typed with its check digit gets a second one. -
02
Size the modules in printer dots
Set Module width to 0.254 mm, TEC-IT's usual MSI size: 2 dots at 200 dpi, 3 at 300 dpi.
-
03
Add the quiet zone
The image ends at the bars: set Quiet zone to 12 modules, 3.05 mm, per side.
What is an MSI barcode?
MSI, or Modified Plessey, is a linear barcode for digits only; TEC-IT's knowledge base names libraries and stores as its users. MSI Data Corporation built it on Plessey Code's encoding principle. Each digit is four bars and four spaces.
Where MSI fits: readers already set up for it
Print MSI for a system that already reads it, and ask which check digits and length it expects. Zebra's DS2208 and Honeywell's Voyager 1450g ship with MSI switched off, and their default lengths differ: 4–55 and 4–48 digits.
Some printers draw MSI natively. Zebra's label language ZPL has an MSI command that adds one mod 10 digit by default, and the AFP Consortium's bar code architecture defines MSI for document printers.
Reliable reads: check digit, reader length, print ratio
MSI characters are not self-checking, so the check digit has to catch misreads; Zebra's DS2208 always verifies one. Its manual warns that a scan line crossing part of the symbol can pass as a shorter number. A fixed reader length prevents that.
Generated wide elements are twice as wide as narrow ones, the ratio AFP recommends for MSI. The drawing shows the example at 0.254 mm: 115 modules, 29.21 mm, plus the quiet zones.
MSI online and in TEC-IT software
Free output is GIF, PNG or JPG; a plan adds SVG and higher print resolution. Guests create one symbol at a time; a free sign-in opens data sheets, and every number in a list gets its own mod 10 digit.
TBarCode SDK and Barcode Studio add one mod 10 digit by default and offer a two-digit MSI method. Barcode Studio imports CSV files or counts serial numbers; TBarCode Office links a barcode to an Excel cell.
MSI at a glance
- Type
- Linear, digits 0–9, not self-checking, 2:1 ratio
- Check digits
- One mod 10 online; also mod 10/mod 10, mod 11/mod 10
- Length
- Up to 14 digits incl. check digits (TEC-IT reference)
- Module width (X)
- 0.254 mm (TEC-IT)
- Quiet zone
- 12X left and right (TEC-IT)
MSI check-digit schemes
Mod 10 for 01234567: weight the digits 2, 1, 2, 1 … from the right and add the digits of the products (26); the check digit 4 tops that up to 30.
- Mod 10/mod 10: a second mod 10 over the number and the first check digit.
- Mod 11/mod 10: mod 11 with weights 2–7 (IBM) or 2–9 (NCR), then mod 10.
Frequently asked questions
Learn more about MSI.
What is the difference between MSI and Plessey?
Which MSI check digit does this generator add?
Why does my scanner not read MSI barcodes?
Why is the last digit missing from the scanned data?
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