Choose Code 39 checksum and verify the printed label

Use standard mode unless the workflow expects Mod-43

Standard Code 39 has no checksum character. When the checkbox is enabled, the engine appends the Mod-43 character before the stop symbol; choose the mode your scanner workflow expects.

Mod-43 character = sum of Code 39 character values modulo 43

Treat CSS dimensions as print targets

The default labels are 70 mm wide and 40 mm high. Browser and printer scaling can change physical size, so print one sample, measure it, and scan it before repeating the batch.

Keep show-price enabled when people need a visible price, but confirm that the SKU is the barcode payload.

Review rows before a full run

Check quantity, SKU characters, checksum selection, label size, and scanner output. The tool does not create inventory records or track scans after printing.