Market Equilibrium Quantity

What is this formula?

Market Equilibrium Quantity calculates the quantity traded when market demand equals market supply.

At this quantity, buyers and sellers agree on the same market outcome and no shortages or surpluses exist.

When to use it

Use this formula when studying competitive markets, equilibrium analysis, and the interaction between supply and demand.

It is derived from the intersection of the linear demand function:

Qd = a − bP

and the linear supply function:

Qs = c + dP

Example

Demand:

Qd = 1000 − 20P

Supply:

Qs = 200 + 30P

Formula:

Qe = (ad + bc)/(b + d)

Substitution:

Qe = ((1000×30)+(20×200))/(20+30)

Qe = (30000+4000)/50

Qe = 680 units

Result:

The market equilibrium quantity is 680 units.

Applications

- Market equilibrium analysis

- Production planning

- Economic education

- Policy evaluation

- Demand and supply forecasting

Note

This formula assumes linear supply and demand relationships. In real markets, equilibrium quantity may be influenced by taxes, subsidies, regulations, market power, and nonlinear behavior.