Basic Overview
Description  The Net Present Value (NPV) function calculates the net present value of an investment by using a discount rate, a series of future payments and an income. 
Signature  NPV(Rate, Cashflow [,Level]) 
Parameters  Rate → The rate of the discount over the time of the period Cashflow → Series of payments or incomes (negative values represents outgoing payments and positive values represent incoming payments) Level → [Optional] The period of time or a sequence over which the calculation is going to be made. If the level is not provided, the lowest time level from cashflow is selected

Notes  The 'Cashflow' node is the leading input node. Rate values are percentages and must be entered/returned as decimals. e.g. 10% → 0.1 If a level is entered, it should be a level of the cashflow node The levels from the rate input node need to be available in the cashflow input node Any level that is in the same dimension as the selected level from the cashflow node, cannot be available in the rate input node. That also counts for all linked levels in this dimension

Limitations  
Example:
Cashflow:
Year  Region  Measure 

2021  Asia  +500 
2022  Asia  100 
2023  Asia  +200 
2021  Europe  100 
2022  Europe  +400 
2023  Europe  +500 
Rate:
Region  Measure 

Asia  0.05 
Europe  0.1 
NPV Result:
With the given cashflow and rate nodes, using the function NPV('Rate', ‘Cashflow') (or NPV('Rate', ‘Cashflow', “Year“)) would give the following result. In this example, the NPV has been aggregated over the years.
Region  NPV 

Asia  558,26 
Europe  615,33 