This is the measure of the net monetary value of goods and services produced by all the nationals of a country after removing the amount or value needed to replace the assets worn out in the process of producing the output in a given period of time, usually one year.

How to get NNP

The value of output required to replace the worn out capital during the production process is known as "Depreciation allowance" or "Capital Consumption allowance". If this NNP = GNP - depreciation (capital consumption) allowance.