How to calculate WIP?

After one production order finish, the amount of WIP will be calculated by system. How to calculate the amount the amount WIP?

Thanks and regard

Made up of material costs, labour hours booked, quantity cost categories.

AX2009 will include fixed and variable overheads depending upon the costing sheet setup.

I think WIP is the amount of semi production. for example, we have 2 work center and the average of WIP is the total of semi production at 2 work center. Can you explain it?