Depreciation means a decline in value over time. In economics, the term is used in two common ways: asset depreciation (capital wearing out) and currency depreciation (a weaker exchange rate).
Asset Depreciation
Asset depreciation allocates the cost of a long-lived asset across the periods that use it. A simple accounting rule is straight-line depreciation:
[ \text{Annual Depreciation} = \frac{\text{Purchase Price} - \text{Salvage Value}}{\text{Useful Life}} ]
In macroeconomics, this concept appears as capital consumption. Net investment is gross investment minus depreciation, which is central for measuring sustainable capital accumulation.
Currency Depreciation
Currency depreciation means one unit of domestic currency buys less foreign currency than before (in a floating exchange-rate system). A weaker currency can improve export competitiveness but also raise import prices and inflation pressure.
Why The Distinction Matters
- Asset depreciation affects profits, taxable income, and measured productivity.
- Currency depreciation affects trade balances, inflation pass-through, and monetary policy choices.
Confusing these two meanings can lead to incorrect interpretations of business performance or national macro conditions.
Policy And Practical Context
Governments influence asset depreciation through tax rules (capital allowances), while central banks influence currency conditions indirectly through interest rates, liquidity, and communication. Both channels feed into investment decisions.