Economics Pad

Supply / Demand Model

Move the sliders for the non-price determinants of demand and supply to shift the curves, click and drag either curve, or grab points A and B to change a curve's slope. Previous positions are kept as faded shadows.

Set your starting position

Move at least one Demand control (slider, drag, or drag point A/B) and one Supply control. Once both have been touched, the original equilibrium is marked as (Q, P) and subsequent moves leave labelled shadows.
○ Demand moved ○ Supply moved
S D Quantity Price
Scenarios

Price Elasticity of Demand (PED)

Drag the blue A and B points on the Demand line to change its slope and recompute PED between them.

Determinants of PED

  • Availability and closeness of substitutes — more substitutes makes demand more elastic.
  • Necessity or luxury — necessities tend to be inelastic; luxuries elastic.
  • Proportion of income spent on the good — small share → inelastic.
  • Time period — over longer periods consumers can adjust, so demand becomes more elastic.
  • Habit-forming or addictive goods — typically inelastic.

Price Elasticity of Supply (PES)

Drag the red A and B points on the Supply line to change its slope and recompute PES between them.

Determinants of PES

  • Time period — longer time allows firms to adjust output, increasing PES.
  • Spare capacity — more unused capacity → more elastic supply.
  • Stock levels of finished goods — higher stocks → more elastic.
  • Mobility of factors of production — more mobile resources → more elastic.
  • Ease of entry and exit of firms — easier entry → more elastic.

Supply

non-price determinants of supply

Demand

non-price determinants of demand

AD / AS Model — Full version

Move the sliders for the components of AD and the factors of production for AS to shift the curves. The previous positions are kept as faded grey shadows so you can compare.

Set your starting position

Move at least one AD slider and one AS slider to set where the model begins. Once both have been moved, the original equilibrium will be marked as (Y, P) and subsequent moves will leave labelled shadows.
○ AD moved ○ AS moved
AS AD Real GDP Price Level SPARE CAPACITY INTERMEDIATE FULL CAPACITY
Scenarios

Aggregate Supply

factors of production

Aggregate Demand

AD = C + I + G + (X − M)