A picket fence is basically the same as a pale fence but you will notice the difference when you sit on them. Pickets are pointy boards and pales are usually rounded or flat on top.
This calculator will calculate the amount of material needed for a picket (pale) fence. It will calculate the actual post spacing based on max post spacing and the picket spacing on desired picket spacing to create a fence with evenly spaced post and evenly spaced pickets on the good side. If you are building a good neighbour fence, pickets on both sides, it will double the amount of pickets needed and you may have to adjust the total amount by one or two pickets needed.
The railing material is in lineal metres needed. That is the exact railing amount. If you buy the material in a store you will have to figure out how many sections you can get out of one length of material. A mill will most likely sell in cut to size lengths.