To ensure a consistent set of metric and inch-based dimension equivalents, a consistent precision (significant digits), method of conversion (inches to millimetres and millimetres to inches), and method of rounding has been established.
Note: The following rules are for use by GS1 technical staff only. Writers and editors should never round numbers provided by technical staff.
Because many barcode symbol widths are defined by a multiple of X-dimensions (modules), the X-dimension is to be rounded to the third decimal place (N.NNN) for X-dimensions stated in millimetres and to the fourth decimal place (N.NNNN) for X-dimension equivalents in inches.
The overall widths (horizontal), heights (vertical) and other dimensions for barcode symbols are to be rounded to the second decimal place (N.NN) for dimensions stated in millimetres and to the third decimal place (N.NNN) for the dimension equivalents in inches.
If the calculation of an equivalent dimension results in a value that is more digits than the precision required, and the digit following the digit to be rounded is a 5 or greater, the value is to be rounded up to the next higher value. If the digit following the digit to be rounded is less than 5, the digit to be rounded remains the same.
The metric equivalent of the GS1 barcode inch dimensions are to be calculated using the dimensions multiplied by 25.4.
□ The nominal X-dimension is 0.0130 in. x 25.4 = 0.330 mm and the total width of the barcode, including Quiet Zones, is 0.330 mm x 113 = 37.29 mm.
The inch equivalent of the GS1 barcode metric dimensions are to be calculated using the dimensions divided by 25.4.
□ The overall width would be 26.73 mm / 25.4 = 1.052 inch. The overall height would be 21.31/25.4 = .839 inch.
Note: Within GS1 standards & guidelines, decimal placement are indicated with a full stop.