Determining the X-Dimension and quiet zones
The X-Dimension is the narrowest bar or whitespace in a barcode. You can use the following formula to determine the X-Dimension of a barcode.
| Variable | Description | Value |
|---|---|---|
| a | Constant | 25.4 |
| b | The number of dots that make up a bar (integer) | 1..n |
| n | The printer’s dots per inch (dpi) | 203/300 |
When scanning a barcode using a barcode verifier, you can deduce the label printer’s dpi using the above formula.
For example, if the barcode verifier gives me an X-Dimension of 334μm, I can determine the what was the intended X-Dimension by trialing different values of n:
b = (25.4 * n) / 334
b = (25.4 * 5) / 0.334 = 380.24 - 5 is not likely as it is not close to either 203 or 300 dpi.
b = (25.4 * 4) / 0.334 = 304.19 - Our number of dots is likely to be 4 as this is close to 300 dpi.
Therefore, the true X-Dimension will be:
(25.4 / 300) * 4 = 0.339
Calculating the quiet zone
The quiet zone for the barcode is to be 10 times the X-Dimension, so 10(0.339) = 3.39mm
Calculating the width of a Code 128 Barcode
The following formulas can be used to calculate the width of a Code 128 barcode excluding quiet zones.
Code128 Subset A/B
Code128 Subset C
| Variable | Description |
|---|---|
| w | Overall barcode width (in mm) |
| c | Number of characters being encoded |
| x | X-Dimension (in mm) |
Note: The above formulas do not apply to barcodes that comprise of multiple subsets.