National income is a technical term. We need to be specific about its use. Hence, in national income estimation different concepts of national income have been developed, e.g., gross national  market prices, gross national product at factor costs. net domestic product at market prices, etc.

These different aggregates are interrelated.
The choice of a specific aggregate depends upon the nature of economic enquiry at and. In order to understand the nature of different aggregates of national income, he following relationships may prove useful:

1.    Gross and Net
                       Net Product = Gross Product – Deprecation
                                              ( or consumption of fixed capital)

or                    Gross Product = Net Product + Depreciation.

2.    Domestic Product and National Product
           National Product = Domestic Product + Net Factor Income from Abroad
                                              (NFIA).

3.    Product at Market Prices and Product at Factor Costs
Product at Factor Costs = Product at market prices – Net Indirect Taxes.
Product at Market Prices = Product at Factor Costs + Net Indirect Taxes.

Gross Domestic product at Market Prices (GDP_MP) is the sum total of the money value all final goods and services produced in the domestic territory of a country during year.

It includes :
                           
•    All final goods and services produce within the domestic territory by both normal residents and non-residents.
•    Only new goods and services.
•    Commission paid on transactions in second-had goods and financial capital
•    Imputed value f goods for self-consumption.
•    Imputed value of (i) free residential accommodation, food, clothing and other non-monetary benefits, and (ii) rent on the self-occupied houses.

It does not include:
•    Intermediate goods
•    Second-hand goods
•    Financial claims
•    Self-consumption goods and services
•    Transfer payments
•    Capital gains
•    Income earned through illegal means.

While GDP_MP includes final goods and services produced by all normal residents and on-residents within the domestic territory of the country, GNP_MP
•    includes production by normal residents abroad ; and
•    excludes production by non-residents in the domestic territory, i.e.,

GNP_MP = GDP_MP + Factor income earned by normal residents
                                     abroad – Foctor income earned by non-residents in the domestic territory.
or             GNP_MP = GDP_MP + Net Factor Income from Abroad
                                = GDP_MP + NFIA.

Thus, we can define GNP_MP as the market value of the final goods and services produced in an economy during and accounting year, including net factor income from abroad.

NDP_MP is the market value of net output of final goods and services produced in the domestic territory of a country by its normal residents and non-residents during accounting year.....

NDP_MP is obtained by subtracting the value of depreciation from the GDP_MP i.e.,
                              NDP_MP = GDP_MP – Depreciation.

NNP( ) is the market value of net output of final goods and services produced by an economy during an accounting year and net factor income abroad.
NNP( ) can be obtained either as

                                NNP_MP = NDP_MP+ NFIA
                                NNP_MP = GNP_MP – Depreciation

Depreciation is cost of consumption of fixed assets, and as such this cost is to be deducted from the gross product to estimate net income earned by the community.

NDP_FC is the sum of net values added by all the producers in the domestic territory of a country during an accounting year. NDPMP is calculated as follows:
                                NDP_FC = NDPMP – Indirect Taxes + Subsidized
                                            = NDPMP – Net Indirect Taxes
                                NDP_FC= Compensation of Employees + Operating Surplus + Mixed
                                                Income of the self-employed

Indirect taxes raise the market prices of goods and services. Indirect taxes go to the government and not to the factor inputs, hence these are not included in factor costs or payments.

Subsidies accrue to the factors of production and, are therefore, included in factor costs.

NNP_FC is the factor income accruing to the residents of the country during a year. It s the sum of net domestic factor income and net factor income from abroad, i.e.,
                                  NNP_FC = Net Domestic Factor Income + Net factor Income from Abroad Alternatively,

                                   NNP_FC= NDP_FC+ NFIA
NNP_FCis also known as Nation Income.

National product of a country can be generated anywhere in the world where the normal residents of that country work, whereas domestic product is concerned with all normal residents of that country work, whereas domestic product is convened with all production in the domestic territory, whether by normal residents or non-residents.

GNP( ) is the sum of factor cost of the gross product attributable to the factors of production supplied by the normal residents of the country during a year and net factor income from abroad.

                                 GNP_FC= NNP_FC + Depreciation
                                  GNP_FC is also called Gross National Income.

GDP_FC is the sum of the net value added by all the producers in the domestic territory of the country and the consumption of fixed capital during an accounting year.

                            GDP_FC = NDP_FC+ Depreciation
Alternatively,       GDP_FC = GNP_FC – NFIA.

It is the income earned by the private sector. It is defined as that part of factor cost of net domestic product generated in the form of compensation of employees, operating surplus and mixed income which is accrued to the private sector.

Income from Domestic Product = NDP_FC – Income from Property and
accruing to Private Sector                Entrepreneurship accruing to government      
                                                              administrative departments – Saving of non-
                                                              departmental enterprises

Private Income Private Income consists of factor incomes earned within the domestic territory and abroad by private enterprises and workers (factor owner in the private sectors) and current transfers from the government and the rest-of-the world.

                     Private Income = Income from Net Domestic product accruing to the private
                                                  Sector + Net Factor Income from Abroad +Net Transfer
                                                  payments from the Government + Net Current Transfer
                                                  payments from the rest-of-the world+ Interest on National
                                                  Debt

Personal Income is the income actually received by persons from all sources in the from of current transfer payments and factor income.

Persona Income = Private Income-Net saving of Private Enterprises – Corporation Tax

Net saving of private Enterprises
                                                    = Saving of private Enterprises – Net Retained Earnings
                                                       of Foreign Companies

Personal Disposable Income is the income remaining with individuals after deduction all taxes levied against their income and their property by the government.
Persona Disposable Income = Personal Income – Direct Taxes pain by households –
                                                                               Miscellaneous receipts of the
                                                                               Government (i.e., fees and fines pained
                                                                               by the intervals)

Personal disposable income is the income available to persons from all sources to dispose of as they choose.