How to Print Barcode Labels

Products that arrive without a barcode need one printed. MultiPOS generates the code and lays it out for a label printer, and the whole job is getting the millimetres right.

Expect two attempts. Nobody gets label sizing right first time.

Step 1: Measure your labels

Take a ruler to the actual label stock, not the box it came in.

You want three numbers in millimetres: the label’s width, its height, and whether it comes on a continuous roll or as separate labels.

A common size is 28 by 89 millimetres, which is what MultiPOS ships as its default.

Those are the numbers the next step types in, so measure before you open the screen.

Step 2: Set the barcode paper size

Go to DevDiggers Plugins → MultiPOS → Configuration → Printer.

Field	Default	Enter
Page Width	28mm	Your label’s width
Page Height	89mm	Your label’s height, or 0 for a continuous roll
Page Margins	0mm	Usually leave at zero

Page Height of 0 tells the printer the roll is continuous, so it cuts per label rather than per page. If your labels come out in one long strip when they should be separate, this is the field.

Step 3: Set the barcode layout

• Generated Barcode Height defaults to 40mm. That is how tall the bars print, and it has to fit inside the label with room for the number underneath.
• Unit Spacing Offset defaults to 50mm -3mm. It takes two values, vertical then horizontal, and the negative figure pulls labels together sideways so a two-across sheet does not drift apart.
• Print Output Orientation is Vertical (Portrait) or Horizontal (Landscape).

Vertical suits a roll feeding label after label. Horizontal suits an A4 sheet of labels in a laser printer.

Click Save Changes.

Step 4: Print one test sheet

Go to DevDiggers Plugins → MultiPOS → Assign Barcodes.

Find one product, enter a small quantity like 4 in the quantity field, and click Print.

The browser print dialog opens. In it, check two things before you print:

• Margins set to None. Browser margins fight the millimetre values you just entered.
• Scale set to 100%. “Fit to page” silently resizes your barcode and it stops scanning.

Print onto plain paper first. Hold it against a real label and see where the edges land.

Step 5: Adjust and reprint

Compare and correct:

What you see	Change
Bars run off the edge	Reduce Generated Barcode Height or increase Page Width
Big gap between labels	Reduce the first value in Unit Spacing Offset
Labels overlap sideways	Make the second Unit Spacing Offset value less negative
The number under the bars is cut off	Reduce Generated Barcode Height
Everything sits too high or too low	Adjust Page Margins

Every one of those values lives on the same screen as step 2, so a correction is one edit and one Save Changes. Then reprint from the PRINT LABEL controls on Assign Barcodes.

Reprint on paper until it lines up, then print one real label and scan it.

A barcode that prints is not the same as a barcode that scans. Test it with the actual scanner before you print a thousand.

Step 6: Print in bulk

Once one label scans, work through the products that need labels. Enter the quantity you want per product and click Print.

Use the search box to find products rather than paging through the whole catalogue.

Print the quantity you actually have in stock, not a round number. Spare labels for a product you have since reordered at a different price cause more trouble than they save.

Which code gets printed

Whatever is in that product’s barcode field. If the field is empty, the plugin generates one from the product ID or the SKU, depending on Barcode Synchronization under Configuration → General.

Where to go next

• How to Scan Barcodes at Checkout
• Printer Settings for the field reference.
• Assign Barcodes