whats the difference between GDP and national budget
The Evil Overlord
GDP (Gross Domestic Product) is the total value of all goods and services produced in your nation.
Your national budget will never be more than a modest fraction of this number, since the budget is dependent upon the revenue created by taxation, fees, etc charged by your government to maintain its operations. Even the US budget (just proposed) is less than 20% of the US GDP.
to clarify, the GDP is not the value of good, but actually the total money spent in your country. if you build a building, paying for labor and materials, the GDP goes up. if it turns out you built the building crappily and have to tear it down, paying for more labor and probably a wrecking ball, the GDP goes up again. the GDP doesn't make the distinction between good and bad expenditure, and so cannot be said to measure 'value' since there is no value in wrecking a building.