What is Code 39 used for?
Code 39 is a general-purpose format for older scanning equipment that can’t read Code 128. It encodes A-Z, 0-9, and the symbols - . $ / + % space, with no registration or GS1 number required. It’s not a retail product identifier, so there’s nothing to license.
Should you use Code 39 or Code 128?
Use Code 128 unless you specifically know your scanner needs Code 39. Code 39 is physically wider for the same data (30.7 mm against Code 128’s 24.0 mm at the same magnification), yet both formats became unreliable at the identical bar width in our test, so the extra width buys no scanning advantage. See the Code 128 generator if you’re not constrained by older hardware.
How small can Code 39 be printed before it stops scanning?
Down to 65% magnification (X = 0.214 mm) in our test, one step earlier than EAN-13 and UPC-A. Below that, the white gaps between bars close before the bars themselves visibly degrade.
Brother HL-L2375DW mono laser · Plain A4 copier paper · Standard quality · Pixel 9 Pro XL rear camera · Bright indoor light · 2026-08-02