Net domestic product (NDP) is equivalent to the gross domestic product (GDP) less depreciation. GDP is the overall market value of a country’s goods and services, measured over an arbitrary period of time. Depreciation accounts for the decrease in value of assets over this period of time. NDP takes this decrease into account and is defined as the book value of a single country’s goods and services.

Compile the values of investments, consumption, imports, government spending, exports and depreciation for a country over a set period of time.

Calculate GDP by adding up the value of investments, consumption, government spending and exports together. Subtract the value of imports from that amount.

Subtract the value of deprecation from the total GDP.