Spending pressure raises prices when output cannot keep pace.
Demand-pull inflation arises when rising aggregate demand puts upward pressure on the general price level, particularly where output cannot expand as readily. Higher consumption, investment, government purchases or net exports can contribute. With spare capacity, firms may respond substantially through output; near bottlenecks, a larger part of the response can be higher prices. An AD increase can produce a price-level rise, but sustained inflation requires an account of pressures continuing over time. Increased demand for one isolated product does not automatically establish economy-wide demand-pull inflation.
- Demand pressure
- Demand-pull inflation arises when stronger aggregate demand (AD) puts pressure on the general price level. Spending across the economy increases faster than firms can readily expand production.
- Capacity matters
- A bottleneck is a constraint that limits expansion, such as too few skilled workers or full transport capacity. Near these limits, extra spending can produce more price pressure and less extra output.
- Persistence
- Explain repeated or continuing pressures when claiming sustained inflation.
Why the supply response matters
Agents
Some firms may gain sales, but wages, input costs and capacity constraints affect profit; households' real outcomes depend on income adjustment.
Diagnostic evidence
Look for broad spending growth, order books and high capacity use, not simply one rising price.
Worked example: More spending meets limited capacity
Households and firms increase spending across many sectors while factories, transport networks and skilled workers are already heavily utilised. New capacity takes time to install.
- Broad stronger spending raises AD at each general price level.
- Suppliers cannot quickly expand output as much as demand, so price pressure increases alongside any additional production.
- If repeated demand increases continue to outpace the supply response, general price increases can persist.
- Evidence of broad orders, capacity use and spending helps distinguish this mechanism from an imported-input cost shock.
Watch out for this
Every increase in AD causes the same inflation rate regardless of spare capacity.
The supply response matters. The same demand increase can have different output-price effects under different constraints.
Check your understanding
Why might a demand increase create stronger price pressure near capacity?
- Because real output must be exactly zero.
- Because suppliers have less scope to raise real output quickly.
- Because imports cannot exist.