The US has the most national debt by amount (~$39 trillion), but Japan has the highest debt relative to its economy (over 200% of GDP). Debt is the total of past deficits.

The US (about $32.4 trillion) and China (about $20.9 trillion) are the world largest economies in 2026, together making up roughly 42% of world GDP (IMF).

Microeconomics studies individual markets and firms; macroeconomics studies the whole economy – GDP, inflation and unemployment. They are two halves of the same subject.

Developed countries have high incomes and service economies; developing countries rely more on agriculture. The World Bank, IMF and UN each classify them differently.

Nominal GDP uses current prices and includes inflation; real GDP uses constant prices to show true growth. In 2024 US real GDP grew 2.8% (BEA).

GDP measures output by location; GNP and GNI measure residents income. In Ireland, national income (GNI*) was only 57.1% of GDP in 2024 (CSO).

Capitalism means private ownership and market prices; socialism means collective or state ownership. The freest economies average 8x the GDP per capita (Fraser, 2024).

Inflation is a sustained rise in the general price level that reduces the purchasing power of money. US inflation was 2.7% in 2025 (BLS); central banks target about 2%.

A traditional economy is based on custom and subsistence farming, herding and barter. In Chad, 69% of workers are in agriculture (World Bank, 2023).

A mixed economy blends private markets with government intervention. Government spending ranges from about 34% of GDP in the US to 57% in France.