It is very risky to reduce the size of a UPC symbol. The nominal size of a UPC symbol is 1.469" wide x 1.02" high. The minimum recommended size is 80% of the nominal size or 1.175" wide x .816" high. The maximum recommended size is 200% of the nominal size or 2.938" wide x 2.04" high. Larger UPC's scan better. Smaller UPC's do not scan as well or not at all.

Ink spread can also decrease the flexibility of size reduction of a bar code. If a bar code is reduced too much, an attempt to silk screen print it will blur the bars together. This is one of the reasons why it is recommended to keep the bar code within the minimum of 80% of the nominal size.