Tooth pitch is defined as the number of teeth per inch (tpi). 1 inch corresponds to 25,4 mm.

In the WIKUS range a difference is made between constant tooth pitches with regular tooth distance ...

... and variable tooth pitches with differing tooth distance within one toothing interval.

Variable tooth pitches are marked by two measures, e.g. 2-3 tpi. With this, 2 tpi signifies the maximum tooth distance and 3 tpi signifies the minimum tooth distance in the toothing interval.