The layers increase exponentially.
Also, the number of people that misunderstand the purpose of folding a steel billet is ridiculous. More layers =/= better sword. The main purpose of folding is to homogenize carbon content in the steel, which is pretty iffy in consistency if you manufacture it with medieval materials and methods. However, if you can find a way around this by producing a refined steel in the first place (no slag, even carbon distribution, etc), you can skip the folding process. Certain areas of Calradia might have access to purer ore deposits or more advanced means of obtaining steel.