What is a budget deficit?

A budget deficit occurs when expenditure exceeds revenue during a period. Revenue exceeding expenditure creates a surplus. A deficit is a flow over time, while public debt is a stock of liabilities at a particular date. They should not be used interchangeably.

How is the budget balance calculated?

1. Revenue and expenditure coverage Taxes and non-tax receipts are important sources of public revenue. Spending may include personnel, goods and services, investment, transfers and interest. Before comparing figures, establish whether they cover central government or a wider public-sector perimeter. 2. A simple calculation and ratio A budget with revenue of 900 units and expenditure of 1,000 has a deficit of 100. Expressing the deficit relative to GDP accounts for economic size. Ratios based on different accounting coverage may still be misleading to compare. 3. The primary balance Excluding interest expenditure produces the primary balance. A primary surplus can coexist with an overall deficit because of interest payments. A primary surplus of 20 and interest spending of 35 result in an overall deficit of 15.

Causes and consequences of deficits

4. Cyclical and structural factors Economic contraction can lower tax receipts and increase demand for social support. Persistent mismatches between revenue and spending can indicate problems independent of the cycle. One-off revenues or exceptional expenditure can change one year’s appearance. 5. Financing and risk A deficit may be financed through borrowing or existing cash resources. Financing choices affect future interest costs, liquidity and risks. The purpose of a deficit and its financing terms matter alongside its size. 6. Sound assessment Cash versus accrual accounting, off-budget obligations and guarantees should be considered. Deficit reduction can also affect services or investment. Sustainability depends on revenue capacity, spending quality and the medium-term outlook, not just one year’s figure.