GDP

What is it?

The monetary total value produced by all the final goods and services within the country borders within a certain period of time(usually a year or a quarter) is GDP.

It is one of the most important economic factors that we use to understand the economy as a whole.

How do we calculate it?

To understand this first we need to understand what exactly does "final goods and services" mean exactly, to simply put they are the final and finished products.

For example if our country is a bakery, the cake that we make is the product whose value will be counted in GDP, not the flour you brought, not the sugar you brought.
But if some country can not produce the Cake but gives you flour, than that is counted in their GDP.

And also "within country's border" means even if the producer is foreign it counts in the country's border where it is produced.

Problem: While doing this calculation there is a problem of multiple counting because if we just sum up everything we are bound to make errors so we use certain methods to calculate GDP.

Methods to Calculate:

Value Addition Method:

Expenditure Method:

Totaling all of this we get out GDP as :
C + I + G + (X - M).

Income Method:

Ideally all the methods should give same GDP but they don't. Hence we have different ways to understanding GDP.

GDP's Variants

GDP Per Capita

It just means GDP divided by total population.

GDP Per Capita=GDPPopulation

It is kind of used to compare standards of living across countries, for example GDP of India is Huge compared to Norway but GDP Per Capital shows that our standards of living are comparatively lower than that of Norway because of our large population.

GDP Growth Rate

This measures how fast the economy is expanding or growing.
Higher GDP growth rate shows booming economy while lower growth rate indicates recession of economic crisis.
China and India have really good growth rate right now making us amazing economies while other developing countries aren't so booming.

Limitations:

While GDP can be a really nice measure of how well economy is doing in a country, measuring it across space gives us good result but measuring across time gives us results which aren't so good because it doens't account for inflation, purchasing power, currency rates etc. So we have to make adjustments. Those are:

GDP Comparison with Time

Real vs Nominal GDP

Comparing Across Countries

Because countries use their own currency we convert it into one common currency usually the USD to compare them.

Exchange-Rate Comparison

PPP ( purchasing power parity )

Why is this used?

Limitations of GDP as Economic Welfare

GDP doesn't fully capture the whole societal well-being that we think it does, here are some of the cases where it fails:

Excludes Non-Market Activities

Illegal Activities

War and it's Effects

GDP Per Capita and Inequality

Foreign Investments and Tax Havens

Economic Welfare and Understanding